Life Histories of North American Cuckoos, Goatsuckers, Hummingbirds, and Their Allies (continued 3)

Field marks.—A cuckoo may be easily recognized as a cuckoo by its size, shape, and color—a long, slender bird, longer than a robin, with a long tail, olive-brown above and white below; but the two species look very much alike unless the distinctive markings can be clearly seen. The yellow lower mandible of this species can be seen only at short range. But the rufous in the wing feathers is evident in flight, and the lateral tail feathers are conspicuously black, with large terminal white areas clearly defined. At very close range the yellow eyelids of this species may be seen.

DISTRIBUTION

Range.—Temperate North America, the Caribbean region, South and Central America; casual on Bermuda and accidental in western Europe.

Breeding range.—The breeding range of the yellow-billed cuckoo extends north to southern British Columbia (Kamloops); northeastern Oregon (Keenys Ferry); northern Utah (Salt Lake City); northern Colorado (Loveland, Greeley, and Fort Morgan); South Dakota (White River, Yankton, and Sioux Falls); Minnesota (Fosston and St. Paul); Wisconsin (Ladysmith, Waupaca, and New London); northern Michigan (Blaney and Sault Ste. Marie); southern Ontario (Listowel, Rosseau, and Ottawa); northern New York (Watertown and Plattsburg); and southern Maine (Auburn). From this point the breeding range extends southward along the Atlantic coast to Florida (New Smyrna and Kissimmee); the Bahama Islands (Inagua Island); probably the Dominican Republic (Dajabon); and the Virgin Islands (St. Croix). South to the Virgin Islands (St. Croix); Jamaica (Port Henderson); Coahuila (Sabinas River); southern Sonora (Guaymas); and southern Baja California (San Jose del Rancho). West to Baja California (San Jose del Rancho and Cerro Prieto); California (Wilmington, Watsonville, Santa Clara, and Redding); Oregon (Salem); Washington (Grays Harbor, Tacoma, and Seattle); and British Columbia (Victoria, Chilliwack, and Kamloops).

The range as outlined is for the entire species, which has been separated into two geographic races. The yellow-billed cuckoo (C. a. americanus) occupies the eastern part of the range west to South Dakota, Nebraska, eastern Colorado, and Oklahoma, while the California cuckoo (C. a. occidentalis) is found over the rest of the country to the Pacific coast.

Winter range.—The winter home of this species has not been accurately determined, but it extends north to northern Colombia (Santa Marta, Bonda, Medellin, and Antioquia); and Venezuela (San Cristobal, Altagracia, the Orinoco River region, and Nericagua). It has been found at this season east to southeastern Brazil (São Paulo); Uruguay (Rio Negro); and eastern Argentina (Buenos Aires and Lomas de Zamora). South, probably only casually to central Argentina (Lomas de Zamora and Saladillo). West to Argentina (Saladillo and La Riojo); Ecuador (Nono, Chimbo, Cumbaya, and Guapulo); and Colombia (Cienaga and Santa Marta).

Spring migration.—Early dates of spring arrival are: Florida—Melrose, March 12; Daytona Beach, April 9; Pensacola, April 13. Alabama—Autaugaville, April 16. Georgia—Savannah, March 24; Kirkwood, April 7. South Carolina—Charleston, April 14. North Carolina—Raleigh, April 25; Weaverville, May 1. Virginia—Lawrenceville, April 23; New Market, April 26. District of Columbia—Washington, April 27. Pennsylvania—Philadelphia, April 20; Beaver, May 6; Renovo, May 11. New Jersey—Morristown, April 7; Elizabeth, May 9. New York—Shelter Island, May 2; Rhinebeck, May 3; Watertown, May 12. Connecticut—Hartford, May 9; Jewett City, May 10. Rhode Island—Providence, May 11. Massachusetts—Boston, May 4; Beverly, May 15. New Hampshire—Milford, May 11. Vermont—St. Johnsbury, May 27. Maine—Lewiston, May 6; Fryeburg, May 19. Mississippi—Biloxi, April 6; Rodney, April 8; Oakvale, April 10. Arkansas—Helena, April 19; Delight, April 24. Tennessee—Chattanooga, April 10; Knoxville, April 27. Kentucky—Eubank, April 22; Bowling Green, April 24. Missouri—St. Louis, April 28; Kansas City, April 30; Concordia, May 1. Illinois—Rantoul, May 2; Chicago, May 4; Olney, May 5. Indiana—Terre Haute, April 17; Fort Wayne, April 29; Waterloo, May 4. Ohio—Oberlin, April 26; Columbus, April 29; Youngstown, May 7. Michigan—Detroit, May 4; Battle Creek, May 11. Ontario—London, May 8; Guelph, May 12. Iowa—Sioux City, April 30; Grinnell, May 9. Wisconsin—Madison, May 10; Racine, May 10; La Crosse, May 12. Minnesota—Minneapolis, May 6; Winona, May 8. Texas—Fredericksburg, April 1; Kerrville, April 7; San Antonio, April 14. Oklahoma—Skiatook, April 20; Oklahoma City, May 3. Kansas—Ottawa, April 25; Onaga, April 28. Nebraska—Red Cloud, April 29; Lincoln, May 7. South Dakota—Vermillion, May 17. New Mexico—State College, May 25. Arizona—Phoenix, May 1; Tombstone, May 20. Colorado—Longmont, May 20; Denver, May 28. California—Petaluma, April 18; Pico, May 5; Berryessa, May 13. Oregon—Sauvies Island, April 24. Washington—Tacoma, May 3.

Fall migration.—Late dates of fall departure are: California—Murphys, September 1; Vineland, September 22. Colorado—Yuma, September 3; Clear Creek, September 8. Arizona—Tucson, September 8. New Mexico—Mesilla Park, September 7; State College, September 18. North Dakota—Grafton, September 4. South Dakota—Lennox, September 15; Yankton, September 24. Nebraska—Dunbar, September 27; Lincoln, October 5. Kansas—Onaga, October 1. Oklahoma—Copan, September 23; Kenton, September 30. Texas—Bonham, September 25; Swan, September 28; Kerrville, October 19. Minnesota—Minneapolis, October 1; Hastings, October 20. Wisconsin—Madison, September 27; Racine, October 6. Iowa—Grinnell, October 22. Ontario—Galt, October 2; London, October 11; Point Pelee, October 16. Michigan—Detroit, October 8. Ohio—Youngstown, October 12; Columbus, October 19; Oberlin, October 21. Indiana—Sedan, October 13. Illinois—Chicago, October 18; Rantoul, October 24. Missouri—Concordia, October 10. Kentucky—Lexington, October 10. Tennessee—Nashville, October 11. Arkansas—Delight, October 20. Mississippi—Biloxi, October 11. Maine—Fryeburg, September 1. Vermont—St. Johnsbury, September 12. Massachusetts—Marthas Vineyard, September 24; Lanesborough, September 29; Hadley, October 18. Connecticut—Meriden, October 12; New Haven, October 16; Portland, October 17. New York—Rhinebeck, October 1; New York City, October 12. New Jersey—Morristown, October 9; Elizabeth, October 12. Pennsylvania—Beaver, September 27; Philadelphia, October 17; Renovo, November 12. District of Columbia—Washington, October 13. Virginia—Lawrenceville, October 12. North Carolina—Raleigh, October 17. South Carolina—Mount Pleasant, November 7. Georgia—Savannah, October 19. Florida—Pensacola, November 2.

Casual records.—While the yellow-billed cuckoo may be considered only as a casual visitor to Bermuda, an extraordinary invasion was recorded on October 9, 1849, when thousands of individuals suddenly appeared in all parts of the island; a few more have been subsequently reported. During the period from 1825 to 1921 it was recorded fully a dozen times from England, Scotland, Ireland, and Wales, all these occurrences being in fall and mostly during October. One was taken at Bois de Lessines, Belgium, in October 1874, and one was collected at Turin, Italy, on October 28, 1883. Two occurrences have been recorded from the southern part of France, but there is some question that they were correctly identified.

Egg dates.—Arizona: 13 records, June 28 to August 24; 7 records, July 19 to August 22.

California: 55 records, May 15 to August 20; 28 records, June 17 to July 10, indicating the height of the season.

Florida: 19 records, April 12 to August 25; 10 records, April 16 to May 16.

Illinois: 39 records, May 20 to July 19; 20 records, June 4 to 26.

New York: 23 records, May 24 to August 19; 12 records, June 4 to 11.

Pennsylvania: 13 records, June 6 to July 29.

Texas: 34 records, March 22 to June 30; 17 records, May 6 to June 5.

COCCYZUS AMERICANUS OCCIDENTALIS Ridgway

CALIFORNIA CUCKOO

Plate 6

HABITS

This western race of our common yellow-billed cuckoo has been separated on very slight average characters, hardly worthy of recognition in nomenclature. I am inclined to agree with Harry S. Swarth (1929), who says:

Between the eastern and western races of the Yellow-billed Cuckoo there is a slight average difference in size, the western bird being the larger and with a somewhat heavier bill. There is a rather wide range of variation in specimens from any one locality, * * * and the largest eastern birds do not fall far short of the maximum measurements of western specimens. Birds from the Pacific coast are the largest, those from central Arizona near the type locality of occidentalis (the Santa Rita Mountains) are intermediate in size. The subspecies would have a better claim to recognition if restricted to the Pacific coast. * * * The subspecies is certainly as slightly differentiated as any in our Check-list, and I feel that no violence to the facts would result from suppression of the name.

The California cuckoo is nowhere abundant but seems to be generally distributed, in suitable localities, throughout its range from British Columbia to Lower California and other parts of Mexico. In southern California, its favorite haunts seem to be the willow thickets and groves along the beds of streams, or in willow-bottom sloughs, such as the famous Nigger Slough, which formerly existed near Los Angeles. Alfred C. Shelton (1911) describes a favorite haunt in Sonoma County, Calif., as follows: “In the locality of which I write, about five miles southeast of Sabastopol, this stream, known locally as the ‘Lagoon’, becomes, after some winter storm, a turbulent river, flooding acres upon acres of bottom land. In summer its course is marked by a chain of long, rather narrow ponds, many of which are deep. The banks, and much of the intervening space between these ponds, are covered with a thick growth of willow, small ash and scrub oak, while the whole is tangled together with an undergrowth of poison oak, wild blackberry and various creepers, forming, as it were, an impenetrable jungle, hanging far out over the water.”

Spring.—Mr. Shelton (1911) has this to say about the spring movements of the California cuckoo:

Of all migratory birds breeding in this vicinity, the Cuckoo is the last to arrive in the spring, usually appearing during the latter part of May or the first week of June. Upon its arrival, this bird keeps to the higher land, among the oaks and other timber, for a period of two or three weeks before retiring to the willow bottoms to breed. During this period it is wild and shy and difficult to approach. Most active in the early morning, its characteristic note, a loud, clear “kow-kow-kow,” may be heard coming from some tree or group of trees, and perchance an answering “kow-kow-kow,” may come from another tree, some distance away. * * *

After the birds retire to the willow bottoms to breed, their entire attitude changes. When watched and studied in the seclusion of their brush grown haunts, while engrossed with the cares of their domestic duties, the Cuckoos cease to be the wild, shy birds of the upland timber. The familiar “kow-kow-kow” is now forsaken for another note, a low guttural note, “kuk-kuk-kuk,” always uttered by a brooding bird and is the most common call of the cuckoo during the breeding season.

Courtship.—J. H. Bowles (Dawson and Bowles, 1909) writes: “While standing in an open woodland listening to a pair of Cuckoos calling to each other, I saw the male suddenly fly past with a large green worm in his bill. He flew directly to the female, who was perched in a tree a few yards distant, and for a moment or two they sat motionless a few inches apart looking at each other. The male then hovered lightly over his mate and, settling gently upon her shoulders, gracefully bent over and placed the worm in her bill. It was a pretty and daintily performed piece of love-making.”

Nesting.—The nesting habits of the California cuckoo are much like those of its eastern relative. In California its favorite nesting sites are in willow thickets in the river bottoms, or in such swampy lowlands as those referred to above. D. E. Brown writes to me that it is a rare bird in western Washington, and says: “It is found mostly in willow swamps, on the shores of fresh-water lakes, and along streams where the underbrush is thick. I have seldom seen it very far away from fresh water and never in real thick woods. It is a late arrival and does not begin nest building until about the fourth of July. I have found about a dozen occupied nests and only one of these was earlier than the above date; this one was on June 19. All these nests were in willow or wild-rose bushes, except one which was in a spirea bush. All nests were 2 to 8 feet from the ground, or water when built in swamps. The nest is a very frail, small affair composed of twigs loosely put together and lined with finer twigs and sometimes a few leaves. Most of the nests that I have seen have been so very flat and small that they would be exceedingly hard to find if the birds were not on them.”

A nest in the Thayer collection, taken near Kirkland, Wash., on July 7, 1909, was found in an open space in a fir forest in low ground, which was dotted with a second growth of fir and some Osmaronia and Spiraea; it was placed on a branch of a fir on the exposed side of the tree, 9 feet from the ground; it was made of old fir twigs and lined with fresh fir twigs. I have heard of other Washington nests in fir trees.

Major Bendire (1895) says:

The nests here [Arizona] were placed in willow or mesquite thickets, from 10 to 15 feet from the ground, and they were usually fairly well concealed by the surrounding foliage. * * * If the California Cuckoo showed the same parasitic habit of occasionally depositing one or more of its eggs in the nests of other birds, as its eastern relatives are now and then known to do, I believe that I should have observed the fact in southern Arizona. Here I found eight of their nests with eggs, and fully five hundred nests of smaller birds, which nested in similar localities among the willow thickets and mesquite bushes, overrun with vines, in the creek bottoms, but not a single instance of parasitism came under my observation.

Wilson C. Hanna (1937) has published an interesting paper on the nesting habits of the California cuckoo in the San Bernardino Valley, Calif., with a photograph of a nest containing the unusual number of seven eggs; he writes:

I have rather complete notes on twenty-four nests that I have examined in the field, six along Warm Creek and eighteen along the Santa Ana River, and with two exceptions all were in willow trees. In one case the nest was 11 feet up in an alder tree next to the trunk, and in the other case 30 feet up in a cottonwood tree on top of a bare limb partly supported by a few twigs and therefore conspicuous. The last mentioned nest was ten feet higher than any other nest I have seen. Six of the nests in willows were either partly supported by or covered with wild grape vines, another nest was well concealed in the center of live mistletoe, while still another was well hidden in poison oak that was growing over the dead willow tree. A few nests were placed next to the trunks of trees, but by far the most common location was well out on a horizontal or leaning limb. The average height above ground or water was less than thirteen feet and two were only four feet up. A good supply of rope and a ladder were necessary for examining some of the nests without disturbing them or the surroundings.

Nests were always loose structures, of coarse twigs for a foundation, sometimes with a little superimposed grape-vine bark, cottonwood bark, or rootlets. In some cases there was no other lining and eggs could be seen through the bottom of the nest; but usually there were fresh or old leaves, bark strips, or willow cotton. In only one nest was there a feather in the lining. Often the nests were much longer in one dimension than the other, in one case four inches wide and twelve inches long.

Eggs.—The California cuckoo lays usually three or four eggs, occasionally only two. These are indistinguishable from those of the eastern yellow-billed cuckoo and average only slightly larger. The measurements of 43 eggs average 31.1 by 23.1 millimeters; the eggs showing the four extremes measure 35.5 by 23.5, 33.5 by 25, and 27.5 by 21 millimeters.

Food.—Bendire (1895) says that in a brood that he watched, the young were fed “always with a large black cricket (Anabus simplex or purpuratus) * * *. They picked most of these repulsive-looking creatures from grass stalks and low shrubs on which they were feeding, and although there were numbers of them to be found all around, as well as in camp, they generally went off some little distance to get them.”

Mr. Swarth (1929) says that a female, collected in Arizona, “contained in its stomach two green caterpillars and a lizard 100 millimeters long, the latter swallowed entire and rolled into a coil. This seems a startling diet for a tree-dwelling cuckoo, but there is at least one other instance reported, also from the vicinity of Tucson, of a lizard being taken by one of these birds.”

COCCYZUS ERYTHROPTHALMUS (Wilson)

BLACK-BILLED CUCKOO

Plates 8–11

HABITS

The black-billed cuckoo is not so widely distributed as the yellow-billed, being confined in the breeding season to practically the northern half of the United States and southern Canada east of the Rocky Mountains. Within this range it seems to be commoner northward and rarer southward than the other species, ranging farther north and not so far south.

In appearance and habits our two cuckoos are very much alike, and their haunts are similar; both are often found together, or in similar places, though the black-billed is rather more of a woodland bird and rather more retiring than the yellow-billed. William Brewster (1906) says that in the Cambridge region it is “more given to haunting extensive tracts of dry upland woods and to nesting in wild apple trees, Virginia junipers and barberry bushes in remote rocky pastures such as those which lie scattered along the crest and sides of the high ridge between Arlington and Waverley.”

Courtship.—William Brewster (1937a) writes: “On July 15, 1908, I witnessed the coition of two Black-billed Cuckoos in woods near Bethel, Maine. It took place on a branch only three or four feet above the ground. Although performed listlessly and intermittently, it was singularly protracted, for the two birds remained together at least four or five minutes, and did not finally separate until disturbed by my approach, when the male flew away and presently sang once. The female stayed quietly on her perch until I got near enough to see that she was a fully adult bird.”

Nesting.—Most of the New England nests on which I have data were placed at low elevations, 2 to 4 feet above ground, in various small trees, bushes, or thickets. My first nest was the highest, 10 feet up, in the top of a leaning black birch in a strip of swampy woods and brushy thickets along a small brook. Another was 8 feet from the ground in a dense thicket of shrubbery and blackberry vines. Three nests were in small white pines, 3 to 4 feet up, in rather open spaces overgrown with various shrubs and small trees near the edges of the woods; the nests were placed on horizontal branches, against the trunk, and well concealed among the dense branches. Near Asquam Lake in New Hampshire I saw two nests in thick clumps of mountain-laurel in some dense and heavy deciduous woods, where the land sloped down to the lake; the mountain-laurel grew here in extensive patches, but not very high, seldom over 3 or 4 feet; the large and well-made nests were only 2 and 3 feet from the ground, but fairly well concealed.

Some nests of the black-billed cuckoo are very flimsy affairs, but often they are much more substantially built than the nests of the yellow-billed cuckoo. Owen Durfee describes in his notes a well-made nest that he found in a clump of chinquapin oaks near a road in Rehoboth, Mass. It was made of oak twigs and dry fern stalks, many of the twigs being fresh, with leaves attached; it was lined with dry oak leaves and a few fresh ones. It measured 8 inches in outside diameter and 3 by 3½ inches in inside diameter, being hollowed to a depth of 1 inch. There is a beautiful nest in the Thayer collection, taken from a thicket in Lancaster, Mass., 7 feet from the ground; it has a well-made foundation of coarse twigs, tufts of grass, and burs; and it is profusely lined with the green leaves and the cottony catkins of the poplar. S. F. Rathbun writes to me of an interesting nest that he found: “The nest was a saucer-shaped affair made entirely of the burs from the burdock plant, simply stuck together so as to form a shallow receptacle for the eggs. As a lining for the nest a few dry grasses were used, and the burs with the grasses represented the entire structure. The cuckoo certainly showed ingenuity when it made this nest, for it could not have been more simply or easily constructed.”

Dr. T. C. Stephens has sent me some fine photographs (pl. 8) of a black-billed cuckoo’s nest taken at the base of a willow sapling, near the shore of Lake Goodenough, in Union County, S. Dak., and says: “I have observed a rather marked tendency for the black-billed cuckoo in this region to build its nest within a very few inches of the ground or on the ground. This nest in the photograph was several inches above the ground outside the clump, but it might be regarded as a ground nest, because there was quite an accumulation of dirt and weed growth immediately below it. Of course, I have found nests of this species at heights about level with a man’s eyes, also.”

A. Dawes DuBois has sent me the data for eight nests of this cuckoo, as found by him in Tompkins County, N. Y., and Hennepin County, Minn. Two of them were 5 feet above ground, one in the top of a bush covered with grape vines on the steep slope of a ravine and the other in a small larch, in the midst of an extensive willow thicket, half a foot from the trunk of the tree on a branch where two branchlets were attached. One of the lowest two was not over a foot above ground, among weeds 2 feet high; the nest was supported by a small dead branch that had fallen from a tree and lay hidden in the weeds. Others were at intermediate heights in more normal situations. The nest in the small larch tree he describes as made first of some cottony seed pods (ripened willow catkins), then a main structure of woody twigs, and lined with finer twigs, a few grasses and bits of the cottony seed pods; two tufts of dry grass, with roots attached, were at opposite sides of the rim.

Major Bendire (1895) says:

The nests of the Black-billed Cuckoo appear to be slightly better built than those of the Yellow-billed species; the platform is usually constructed of finer twigs, the soft inner bark of cedar, fine rootlets, weed stems, etc., and there is generally more lining. This consists of the aments of oak, white and black ash, and maple, willow catkins, and the flowers of the cudweed or everlasting (Gnaphalium), dried leaves, and similar materials. The majority of the nests are placed in rather low situations, mostly not over 6 feet from the ground, on horizontal limbs of bushy evergreens, pines, cedars, and hemlocks, or in deciduous trees and shrubs, such as the box elder, chestnut, thorn apple, and beech trees; also in hedges, briar and kalmia patches, occasionally on old logs, and now and then even on the ground.

A rather high nest was found by P. G. Howes (1908) near Stamford, Conn. It was about 15 feet from the ground, at the extremity of a limb of “a scrubby apple tree at the foot of a hay-covered field.” He says that, in his experience, the nest “has always been lined with maiden-hair ferns.”

H. W. Flint, of Stamford, Conn., in a letter to Major Bendire (1895), mentions a still higher nest, and says: “I know of one spot in this vicinity where the Black-billed Cuckoo might almost be said to breed in colonies—a sloping hillside near a traveled road. Here I have found seven nests of this species within an hour, none of them placed over 3 feet from the ground. I have also frequently found their nest on a fallen limb, the top of which was resting upon underbrush. As an exception to their low nesting, I once found a nest containing two well-feathered young and two fresh eggs over 18 feet from the ground, placed in the top of a cedar tree, in a dense thicket of other cedars.”

As already mentioned under the preceding species, both cuckoos often lay their eggs in each other’s nests. Thomas McIlwraith (1894) mentions three cases of parasitism on the part of the black-billed cuckoo, as observed by Dr. C. K. Clarke, of Kingston, Ontario; he says:

The first birds Dr. Clarke observed being imposed upon were a pair of chipping sparrows, who raised the young cuckoo at the expense of the family.

Next came a pair of yellow warblers, whose protégé soon crowded out the legitimate occupants of the nest. They were raised from the ground and placed within reach, but the big boy required all the attention of the foster-parents, and the others died. During the whole period, the old cuckoo was always to be found flitting about in a restless manner, as if she had some doubt in regard to the ability of the warblers to take care of her child.

The third case was another pair of chipping sparrows, in whose nest the cuckoo was observed sitting, and from which she did not move till the observers almost touched her. The result was the same as in the other cases. The young cuckoo threw the sparrows out as soon as he had strength to do so.

Eggs of the black-billed cuckoo have also been found in nests of the wood pewee, cardinal, cedar waxwing, catbird, and wood thrush. Under the preceding species will be found a note, published by J. L. Davison (1887), describing the finding of a nest occupied by a robin, a yellow-billed cuckoo, and a mourning dove. Bendire (1895) published an almost identical account of such a remarkable occurrence, on the authority of the same observer, but with the black-billed substituted for the yellow-billed cuckoo. It seems hardly likely that such an unusual happening could occur with both species in exactly the same way, and leaves us in doubt as to which species of cuckoo was involved.

Eggs.—The black-billed cuckoo commonly lays 2 or 3 eggs; sets of 4 or 5 may sometimes be the product of a single pair; but the larger numbers that have been found in their nests, 6, 7, or even 8 eggs, were probably laid by two or perhaps three females, as these birds are notoriously careless about laying in each other’s nests. Bendire (1895) says: “The eggs of the Black-billed Cuckoo are more nearly oval than elliptical oval, and shorter and rounder than those of the Yellow-billed Cuckoo, and much more deeply colored. Like these, they are unspotted; the shell is thin and fine grained, with little or no gloss. Their color is difficult to describe exactly, varying from nile blue to pale beryl green, and occasionally the shell shows a decidedly marbled appearance, caused by different shades running into each other. * * * Aside from their deeper color, they are also readily distinguished from eggs of the Yellow-billed Cuckoo by their smaller size.”

Eggs that I have seen in collections I should describe as “pale glaucous green,” “dull opaline green,” or “microline green” and varying from oval to elliptical-oval. Some of these, as well as some of those included in the following measurements, may be yellow-billed cuckoos’ eggs, as the two are probably not always recognizable with certainty. The measurements of 54 eggs, presumably of this species, average 27.18 by 20.57 millimeters; the eggs showing the four extremes measure 30.48 by 22.86, 22.61 by 18.80, and 25.40 by 18.29 millimeters.

Young.—Incubation is shared by both sexes and lasts for about 14 days. As the eggs are often laid at infrequent intervals, it is not unusual to find young birds of different ages, or even eggs and young, in the same nest. Both sexes assist in the care of the young and are devoted parents; even when an egg is hatched by a foster parent, the mother cuckoo does not seem entirely to lose interest in her youngster, as related above. On the other hand, William H. Moore (1902a), of Scotch Lake, New Brunswick, says: “I have known this bird to desert its young when the nest was molested, and after the young died they were covered with leaves by the adults.” Cuckoos are careless about removing the cast-off shells, which are often found in the nest after the young have hatched. The young remain in the nest 7 to 9 days after hatching and then become quite precocial. While in the nest the young are fed by their parents in a rather peculiar manner, of which Dr. Thomas S. Roberts (1932) writes:

When the old bird returns, the food, which is very likely to be live caterpillars, is concealed in the throat. As a nestling raises its head with open mouth and rapidly vibrating wings, the parent thrusts its bill deeply into the open maw and the young bird grasps securely the smooth bill of the old bird, in which action it is greatly aided by several soft papillae or disks in the roof of the mouth. Then, with a slow, pumping motion, the squirming caterpillars are transferred with some difficulty from one mouth to another. The process is a slow one, the birds being attached a minute or more and the transfer aided, apparently, by a sucking effort on the part of the nestling.

When a young Cuckoo opens its mouth widely there are visible, in the roof of the mouth, a number of large, flat-topped, white papillae or tubercles, arranged symmetrically, the function of which is plainly to make it possible for the nestling to maintain its hold on the parent’s bill, which is smooth and tapering. A small finger-tip inserted well down into the open, upturned mouth of a nestling is seized tightly and a sucking motion is distinctly perceptible. [Pl. 10.]

Prof. Francis H. Herrick (1935) has made a thorough study of the home life of the black-billed cuckoo, and I cannot do better than to quote a few of his remarks on the behavior of the young. After describing the peculiar appearance of the newly hatched young, he says:

More remarkable than anything about its appearance, however, is the muscular vigor and endurance the cuckoo displays at this tender age, for it seems to be able to withstand heat, hunger, and general neglect that would be fatal to the young of most wild birds. I soon found by experiment that when barely three hours out of its shell this little cuckoo could hang suspended by a leg or even by a single toe for upwards of a quarter of a minute, and that it could raise itself up until its bill was well over the twig that it grasped with both feet; and in a short time it was able to raise itself on to the twig, or even to draw itself up with the power of one leg, which implies an extraordinary muscular development. * * * Though born blind and essentially naked, the young black-bill is neither deaf nor dumb, and in proportion to its size it is probably the strongest and most enterprising altricial nestling on the North American continent. * * *

Like other nestlings, the cuckoo lies flat, with toes clenched, and holds to its fragile nest with a firm grip. Attempt to remove it, and it is likely to pull its nest to pieces rather than loose its hold; or it may even drag out a fellow-nestling, reminding one of crayfishes or lobsters, in the handling of which one may also get a living chain. Should you succeed in displacing a bird, its claws will rapidly open and close in its desperate search for any object to clasp, for a contact stimulus afforded by any solid body can alone satisfy this strong reflex. * * *

At the age of about six days the nestling cuckoo has reached that peculiar transitory state which we may call the “quill” or feather-tube stage. * * *

Towards the end of this brief and unique stage the behavior of the young bird changes in marked and rapid fashion. It indulges in new attitudes, acquires new call and alarm-notes, shows fear, and begins those preening or combing movements which are to effect a relatively sudden and altogether surprising change in its appearance. * * *

In one instance the first preening action was noticed on the sixth day; thereafter this kind of activity became frequent, and the bird would comb every “quill” within reach, drawing the mandibles over it from base to apex. Then, with apparent suddenness, at the close of the seventh day the transparent horny sheaths began to give way at their base—instead of wearing off gradually from apex to base in the usual fashion—and were raked off by the mouthful. * * *

Fear may become manifest as early as the sixth day, when a frightened bird will sometimes clear the nest at a bound and, seizing a branch with both feet, hold firmly to it. Should it drop to the ground, it can make off with surprising speed. If captured and held, it will emit loud, explosive squeals, than which nothing seems to arouse its parents to quicker attack or bolder measures. Replace it in the nest, and it spreads its wings, stiffens, and lies flat with every feather-tube on end; and it will repeat these defensive measures as often as it is touched or disturbed. * * *

When from seven to nine days old, with half of its feathers unsheathed, the cuckoo suddenly leaves its nest and enters upon a climbing period, which lasts about a fortnight or until it is able to fly. At one of my observation stations I saw three young birds leave their nest in succession, and the procedure in the case of the oldest one was particularly interesting. This bird, which had been sitting in the bright sunshine, for the day was not uncomfortably warm, of a sudden moved to one side of its platform. After having combed off several mouthfuls of feather-sheaths, it sat upright for some minutes and gazed into its outer world. Then, directing Its attention to a small branch and ducking its head as if contemplating flight, with a leap it cleared the nest, and, catching hold of a twig, with both feet, it swung free with acrobatic dexterity. In another moment it had pulled itself up and was comfortably perched. If such a first perch is placed in the shade and the young bird is promptly fed, it may keep to it for a long time; but it can move about, and should it drop to the ground, it can mount to safety again.

The vertical position assumed by young cuckoos, probably as a hiding pose, has been noted by several observers, but the following incident reported to me in a letter from Frederic H. Kennard, is quite unusual; he says: “I had just been investigating a big highbush blueberry bush, looking for a nest, when I discovered, to my surprise, a fledgling black-billed cuckoo, squatting on a twig about 6 feet from the ground. The little bird, which really was not able to fly, was squatting on a limb, just as little birds ordinarily do; his wing feathers were fairly well developed, but his tail was only about a quarter of an inch long. When I parted the branches a trifle, so that we could see him better, and finding out that he was discovered, he promptly assumed an almost perpendicular position, with his neck stretched out almost unbelievably and his bill almost straight in the air; and there he sat, immovable, with his bill in the air like a bittern, only oscillating a trifle when the branch on which he was sitting was disturbed a little by the breeze.

“My youngest son, Jack, being interested in the peculiarities of cuckoos’ feet, attempted to pick him off the limb; the little bird fluttered to the ground, where he picked him up. When we had duly examined and discussed the arrangement of his toes, Jack endeavored to put the little fellow back exactly where he had been when we first disturbed him. Then, as he endeavored to replace him on the limb, he suddenly went limp and, apparently, passed out in his hand, frightened to death, as I supposed. He was perfectly limp and my impression is that his eyes were closed. Jack finally, in trying to get him to stay on the limb, hung him across the limb by the neck, with his head across one side and his body down the other side. Just then there came a little breeze, the body dropped, and that little bird simply scuttled in under the ferns. It was the most astonishing performance that I ever witnessed, first the stake-driver attitude, as a protective position, and then playing dead.”

Plumages.—Professor Herrick (1935) says of the newly-hatched young cuckoo: “Although most birds emerge from the shell wet with the amniotic fluid, the cuckoo just mentioned came out quite dry. It was two and one-half inches long and weighed less than a quarter of an ounce (or 7.4 grams). Its skin was coal-black, sparsely sprinkled with sharply contrasting snow-white ‘hairs’—in reality the feather-tubes of a rudimentary down which never unfolds. These primitive feather-tubes are later pushed out by those of the juvenal contour feathers and for about a week are borne upon their tips, thus giving them a peculiar flagellate appearance.”

When about six days old, the young cuckoo “bristles like the fretful porcupine in every feather-tract”; these bristles are the feather-tubes of the juvenal plumage, referred to above. At about this age, the young bird begins the “combing” process, by which the sheaths of these feather tubes are removed, as described above, and a marvelous change begins to take place in a remarkably short time, as the sheaths are removed and fall in a shower in and about the nest. Professor Herrick (1935) says: “Thus at one stroke one or more of the juvenal contour feathers are exposed and quickly fluff out in all their shapely proportions. * * * The change actually occupies about twelve hours, and it is really not complete, since the sheaths of the wing- and tail-quills flake off gradually, as in other birds, and those feathers of head and neck out of reach of the ‘comb’ remain sheathed for a considerable time longer.”

By the time that the young bird leaves the nest, at the ago of 8 or 9 days, it is in nearly full juvenal plumage; the wings are fairly well grown, but the tail is still very short. In this plumage the soft plumage above is “buffy brown,” each feather tipped with white; the under parts are silvery white, tinged with pale gray on the belly and with pale buff on the breast and throat. During late summer and early fall, most, if not all, of this juvenal contour plumage is molted and replaced by the first winter plumage, but the flight feathers of the wings and tail are retained until spring. This first winter plumage is much like that of the adult, but it is more brownish on the head and back and more greenish olive on the scapulars than in adults; the throat is more buffy and the upper breast more grayish buff than in the adult; the young bird’s tail is quite different, the grayish white tips are smaller and are not bordered inwardly with the dusky space, which is clearly visible in the adult tail. The molts are apparently the same as in the yellow-billed cuckoo; the adult plumage seems to be acquired before the young birds return from their first winter in the south, but we have no specimens showing a spring molt.

Food.—The black-billed cuckoo is just as good a caterpillar destroyer as the yellow-billed; in fact the food habits of the two species are almost identical in all respects. An abundance of caterpillars in a locality is very likely to bring with it an invasion of cuckoos. Frank L. Farley writes to me: “As far as I am aware, the black-billed cuckoo was unknown in central Alberta until the summer of 1923. That year the central portion of the Province was infested with tent caterpillars, which, in 1924–25, assumed plague proportions. Entire bluffs of poplar trees, several acres in extent, were entirely denuded of their leaves, while houses and other buildings were overrun with the pests.” In June 1924 the cuckoos began to appear for the first time, birds entirely unknown to the residents. “Although caterpillars gradually disappeared after 1925, cuckoos were reported from widely separated parts of central Alberta, the most northerly one being about 150 miles north of Camrose, which is in latitude 53° N. The presence of cuckoos and caterpillars in the same territory during these years would tend to bear out the claims of other observers, that the insects are particularly relished by these birds, which, in some uncanny manner, are able to locate infested territory far removed from their usual place of residence.”

Forbush (1927) says:

In seasons when caterpillars of any species are abundant, cuckoos usually become common in the infested localities. They follow the caterpillars, and where such food is plentiful, the size of their broods seems to increase. During an invasion of forest tent caterpillars in Stoneham, Massachusetts, in May, 1898, Mr. Frank H. Mosher watched one of these birds that caught and ate 36 of these insects inside of five minutes. He saw another in Malden eat 29, rest a few minutes and then eat 14 more. In July, 1899, he reported a family of these birds in a locality infested with the gipsy moth, and said that they were eating large quantities of gipsy caterpillars. In June, 1895, Mr. Henry Shaw reported great numbers of these cuckoos in Dorchester feeding on the same pests. The late Professor Walter B. Barrows, of Michigan, an extremely conservative ornithologist, is responsible for the statement that in several instances remains of over 100 tent caterpillars have been taken from a single cuckoo’s stomach. The Black-billed Cuckoo, because more common than the Yellow-billed, is the species that most commonly attacks this insect in New England orchards. During an invasion of army worms, Professor S. A. Forbes found that 95 per cent of the food of this species consisted of that caterpillar.

F. H. King (1883), writing of the food of the black-billed cuckoo in Wisconsin, says: “Of thirteen specimens examined, nine had eaten caterpillars—among them were eight of the fall web-worms (Hyphantria textor), thirty-three of the oak caterpillars (Dryocampa senatoria), one of the Io caterpillars (Saturnia io), six of the antiopa caterpillars (Vanessa antiopa), and one of the caterpillars of the archippus butterfly (Danais archippus). One contained five larvae of the large saw-fly (Cymbex americana); six, twenty-five grasshoppers; one, a cricket; two, ten beetles; and two, two harvest-men.”

Other authors have charged this cuckoo with eating minute mollusks and other small animals, fishes and aquatic larvae, fruits and berries, and even the eggs and young of small birds. On the latter point, Henry D. Minot (1877) says that “they do great mischief in destroying the eggs of other useful birds. Like arrant cowards, as they are, they take opportunities to approach stealthily the nests of many birds, whom they would be afraid to encounter, and then feast on the eggs of the absent parents, after which they hurry away. They are scarcely less destructive in this way than the black snakes, though I have never known them to kill young birds.”

Behavior.—The two cuckoos are so much alike in haunts, habits, and behavior that most of what I have said about the yellow-billed would apply equally well to this species. The black-billed is rather more swift on the wing than the other, but it flies in the same graceful manner. It is the same shy recluse of the shady retreats, among the dense foliage of the woods and shade trees, unafraid to frequent the orchards and gardens in search for its food, but shunning any intimacy with human beings; we hear its wandering voice but seldom see more than a fleeting glimpse of its graceful form as it fades away into the shadows.

In defense of its eggs or young the black-billed cuckoo is often quite courageous. Olive Thorne Miller (1892) writes charmingly of her experiences with an incubating pair of these cuckoos; she watched them change places on the nest, and found the female quite confiding, but the male never became reconciled to her presence:

It happened that I arrived when the mother was away, and the head of the household in charge. No sooner did I appear on the path than he flew off the nest with great bustle, thus betraying himself at once; but he did not desert his post of protector. He perched on a branch somewhat higher than my head, and five or six feet away, and began calling, a low “coo-oo.” With every cry he opened his mouth very wide, as though to shriek at the top of his voice, and the low cry that came out was so ludicrously inadequate to his apparent effort that it was very droll. In this performance he made fine display of the inside of his mouth and throat, which looked, from where I stood, like black satin. * * *

Finding that his voice did not drive me away, the bird resorted to another method; he tried intimidation. First he threw himself into a most curious attitude, humping his shoulders and opening his tail like a fan, then spreading his wings and resting the upper end of them on his tail, which made at the back a sort of scoop effect. Every time he uttered the cry he lifted wings and tail together, and let them fall slowly back to their natural position. It was the queerest bird performance I ever saw.

On another day, she says: “We had not waited long when the head of the cuckoo family appeared. He saw us instantly, and, I regret to say, was no more reconciled to our presence than he had been on the previous occasion; but he showed his displeasure in a different way. He rushed about in the trees, crying, ‘cuck-a-ruck, cuck-a-ruck,’ running out even to the tip of slender branches that seemed too slight to bear his weight. When his feelings entirely overcame him he flew away, and though we remained fifteen minutes, no one came to the nest.”

E. A. Samuels (1883) writes:

Like the other, the Black-billed Cuckoo is very cowardly, and is quickly driven from the neighborhood of the nest of almost any of the other birds. If a robin, or other bird of equal size, discover one of these, to him pirates, in the vicinity of his nest, he immediately assaults the intruder, with loud outcries, pouncing upon him, and pecking with great ferocity. Others of his neighbors, who are near, join in the attack; the Cuckoo, in retreating, dives into the recesses of a stone wall, or the first secure retreat available; very seldom taking to his wings, as another bird would do, I have known of a cuckoo being driven into a barn by a Blue-bird (S. sialis), who sat perching on a fence outside for several minutes, keeping his enemy prisoner; and the latter, when pursued and captured by myself, preferred being my prisoner to facing his enemy outside.

Voice.—One cannot always distinguish with certainty all the notes of the black-billed cuckoo from all those of the yellow-billed. Many of the notes are much alike in both species. The notes of the black-billed are, as a rule, softer and more liquid than those of the yellow-billed and not so deep-toned.

The ordinary “song” of the black-billed is preceded by a gurgling note, and the rest of the long song is uttered in regularly measured time, not retarded at the end, as is that of the yellow-billed, and the notes are given in couplets or triplets, one syllable in each set being accented. Dr. Charles W. Townsend (1920a) describes it very well as follows: “The full song may be described as a preliminary harsh clearing of the throat followed by from six to twelve short coughs which in turn are succeeded by the more pleasing doublets and triplets of cows. The Yellow-billed Cuckoo repeats his cows or cowks in regular order without dividing them into sets and they sound as woodeny as if he were striking a plank with a mallet.”

Aretas A. Saunders (1929) says: “The bird has a variety of calls. One consists of a gurgling note followed by single notes in even time, ‘krak-ika kuh kuh kuh kuh kuh kuh kuh kuh’. Another is a series of groups consisting of two to six notes repeated many times, with one of the notes strongly accented, such as ‘kuka kuka kuka,’ or ‘kakukaka kakukaka kakukaka.’ I have known a bird to repeat such phrases over a hundred times without stopping.”

The notes of the black-billed cuckoo are often given on the nest or while the bird is in flight, and they may be heard at all hours of the day or night. Both cuckoos are said to be more noisy just before a rain, hence the name “rain crow.”

Mr. Brewster (1937a) says that “both species coo in the same subdued, mournful, dovelike tones, but when so engaged, the Yellow-bill always utters only a single note at a time, and then waits at least a second or two before following it with another precisely similar; whereas the cooing notes of the Black-bill are invariably doubled or trebled or quadrupled, or perhaps even quintupled, yet separated from one another within such grouping by scarcely appreciable pauses.”

Gerald H. Thayer (1903) has given an interesting account of what he calls “the mid-summer, mid-night, mid-sky gyrations of the Black-billed Cuckoo, as noted by my father and me for three consecutive seasons in the southwestern corner of New Hampshire”:

Several years before we discovered the nocturnal-flight phenomenon, we began to be puzzled by the extreme frequency of Cuckoo calls on summer nights. * * * They uttered both the cow-cow notes and the rolling guttural call; but the guttural was much the commoner of the two, except on dark, foggy nights, when the case was usually reversed. * * * The birds were often so far up as to be only faintly audible when directly overhead, with no obstructions interposed; and this on a still night would seem to mean an elevation of at least a hundred and fifty yards. They sometimes flew lower, however, and on cloudy nights often moved about barely above the tree-tops.

* * * On the evening of July 11—a pitch-dark evening with a thunder-shower lowering,—they were remarkably noisy, both sitting in trees and flying high in air. The seated ones, of which I heard only two, made the cow-cow notes, while all the flying ones made the liquid gurgle. I heard this note overhead between thirty and forty times in the course of about three hours, during half of which time I was afoot on the road.

Field marks.—This bird may be recognized as a cuckoo by its size, shape, and general coloration. It can be distinguished from the yellow-billed cuckoo by the absence of the distinguishing marks of the latter, the cinnamon-rufous in the wings, and the conspicuously black-and-white lateral tail feathers.

The wings of the black-billed cuckoo are practically uniform in color with its back; and the lateral tail feathers are dark gray, with inconspicuous, grayish-white, smaller tips, bordered inwardly with a dusky spot. The wholly black bill and the red eyelids can be seen only at short range.

DISTRIBUTION

Range.—Southern Canada and the United States east of the Rocky Mountains, south in winter to northwestern South America. Accidental in Italy, the Azores, and Ireland.

Breeding range.—The breeding range of the black-billed cuckoo extends north to southern Saskatchewan (Johnstone Lake, Muscow, and Indian Head); southern Manitoba (Carberry, Portage la Prairie, and Shoal Lake); northern Minnesota (Crooked Lake); southern Ontario (probably Goulais Bay, Toronto, and Stirling); Quebec (Hull, Montreal, probably Quebec, and probably Kamouraska); New Brunswick (Scotch Lake); probably Prince Edward Island (North River); and Nova Scotia (Wolfville and Pictou). From this point the range extends south along the seaboard to North Carolina (Raleigh and Winston-Salem); Tennessee (Beersheba Springs and Nashville); northwestern Arkansas (Rogers); eastern Kansas (Lawrence and Clearwater); Nebraska (Red Cloud, Kearney, and Antioch); and southeastern Wyoming (Wheatland). West to eastern Wyoming (Wheatland and Dayton); eastern Montana (Terry); and Saskatchewan (Johnstone Lake).

The species has been detected in summer on several occasions west of its breeding range. Among these are: Colorado (Fort Morgan, Clear Creek, Fort Collins, and Wray); Wyoming (Laramie); Montana (Fort Keogh, Knowlton, and Billings); and western Saskatchewan (Eastend, Skull Creek, Medicine Hat, and Big Stick Lake). On June 23, 1924, a partially completed nest was found near Camrose, Alberta, a range extension that for the time being must be considered unusual (see remarks under “Food”). The species also was recorded at Godbout, Quebec, on August 11, 1885.

Winter range.—Available information indicates that in winter this species is concentrated in northwestern South America: Colombia (Antroquia, Medellin, and Bogota); Ecuador (Guapulo, La Carolina, Daule, Puna Lake, and Lechugal); and northern Peru (Huamachuco).

Spring migration.—Early dates of spring arrival are: Florida—Hastings, April 13; Eau Gallie, April 27; Pensacola, May 2. Alabama—Scottsboro, April 18; Barachias, April 22. Georgia—Atlanta, April 24; Athens, April 27. South Carolina—Frogmore, April 24; Spartanburg, April 29. North Carolina—Raleigh, April 15; Piney Creek, May 4. Virginia—Blacksburg, April 26; Lynchburg, May 8. District of Columbia—Washington, April 30. Maryland—Baltimore, April 20. Pennsylvania—Jeffersonville, April 30; Ridgway, May 6; Doylestown, May 9. New Jersey—Milltown, May 2; Passaic, May 7. New York—Medina, May 3; New York City, May 9; Rochester, May 15. Connecticut—Fairfield, May 1; Hadlyme, May 4; New Haven, May 7. Rhode Island—Block Island, May 6. Massachusetts—Belmont, May 4; Marlboro, May 6; North Amherst, May 12; Danvers, May 12. Vermont—Clarendon, May 12; St. Johnsbury, May 13; Wells River, May 18. New Hampshire—East Westmoreland, May 16; South Hooksett, May 16; Concord, May 21. Maine—South Portland, May 11; Winthrop, May 15; Waterville, May 20. Quebec—Montreal, May 10; Hatley, May 28. New Brunswick—Scotch Lake, May 27. Nova Scotia—Halifax, May 12; Wolfville, May 18. Louisiana—Avery Island, April 12. Mississippi—Bay St. Louis, April 14. Arkansas—Fayetteville, April 30; Broma Towns, May 2. Tennessee—Knoxville, April 12; Tate, April 26. Kentucky—Lexington, May 1; Bowling Green, May 6. Missouri—Jonesburg, May 3; Montgomery City, May 4; Columbia, May 7. Illinois—Rantoul, April 17; Elgin, May 5; Glen Ellyn, May 7. Indiana—Bloomington, April 26; Richmond, April 27; Vincennes, May 7. Ohio—Oberlin, May 1; Columbia, May 2; Upper Sandusky, May 3. Michigan—Detroit, May 1; Brant, May 3; Sault Ste. Marie, May 11. Ontario—Guelph, April 19; Ottawa, May 7; London, May 9. Iowa—McGregor, April 24; Mason City, April 30; Wall Lake, May 3. Wisconsin—Racine, May 8; Beloit, May 10; Whitewater, May 11. Minnesota—Montevideo, April 13; Anoka County, May 5; Excelsior, May 13. Oklahoma—Tulsa, May 3; Norman, May 5. Kansas—Fort Leavenworth, May 6; Bendena, May 8; Clearwater, May 9. Nebraska—Valentine, May 1; Red Cloud, May 11; Omaha, May 13. South Dakota—Yankton, May 1; Huron, May 13; Forestburg, May 15. North Dakota—Grafton, April 25; Antler, May 3; Jamestown, May 23. Manitoba—Aweme, May 20; Pilot Mound, May 24; Reaburn, May 26. Saskatchewan—Muscow, May 12; Indian Head, May 20.

Fall migration.—Late dates of fall departure are: Manitoba—Margaret, September 3; Aweme, September 14. North Dakota—Fargo, September 13; Cando, September 18; Argusville, September 22. South Dakota—Forestburg, September 6; Sioux Falls, September 22; Lennox, October 14. Kansas—Cimarron, September 2; Osawatomie, September 22. Minnesota—Elk River, September 27; Red Wing, October 2. Wisconsin—New London, September 24; Racine, September 24; Madison, September 26. Iowa—Wall Lake, September 28; Osage, October 10; McGregor, October 20. Ontario—Ottawa, September 16; Point Pelee, October 18. Michigan—Charity Island, September 20; Grand Rapids, September 26, Detroit, October 9. Ohio—Saybrook, October 1; Berlin Center, October 12; Columbus, October 15. Indiana—Indianapolis, October 2; Fort Wayne, October 12; Bicknell, October 18. Illinois—Rantoul, October 4; La Grange, October 7; Glen Ellyn, October 21. Missouri—Columbia, October 4; St. Louis, October 16. Kentucky—Danville, October 5; Bowling Green, October 18. Mississippi—Bay St. Louis, October 11. Nova Scotia—Sable Island, September 25. Quebec—Montreal, September 5. Maine—Orono, September 21; Winthrop, October 20. New Hampshire—Jefferson, October 3; Durham, October 5. Vermont—Wells River, September 14; Woodstock, September 18. Massachusetts—West Groton, September 30; North Truro, October 13; Harvard, October 16. Rhode Island—Providence, October 23. Connecticut—New Haven, September 28; East Portland, October 3; Meriden, October 8. New York—Hyde Park, October 6; New York City, October 10. New Jersey—Elizabeth, October 3; Sandy Hook, October 5; Milltown, October 24. Pennsylvania—McKeesport, October 11; Jeffersonville, October 13; Pittsburgh, October 16. District of Columbia—Washington, October 28. Virginia—Naruna, October 18. North Carolina—Chapel Hill, October 3; Raleigh, October 10; Hendersonville, October 12. Georgia—Atlanta, October 14; Thomasville, October 21. Alabama—Autauga County, October 16. Florida—College Point, September 28; Pensacola, October 23.

Casual records.—While the black-billed cuckoo does not migrate regularly through the Caribbean region it has been recorded on Dominica (September 30, 1904), Tobago, and Trinidad. Gundlach is alleged to have taken a specimen in May (year?) near Cardenas, Cuba, and there is a somewhat doubtful record from the Isle of Pines on May 11, 1909. Specimens were taken in Bermuda in October 1874 and also in April and May 1875. The Ponta Delgada Museum has an undated specimen taken at San Miguel, Ponta Delgada, Azores; a specimen taken in 1858 near Lucca, Italy, is preserved in the Museum of the University of Pisa; and one was taken on September 25, 1871, at Killead, County Antrim, Ireland.

Egg dates.—Illinois: 13 records, May 7 to July 20; 7 records, June 1 to 26, indicating the height of the season.

Massachusetts: 20 records, May 19 to June 20; 10 records, May 30 to June 10.

Michigan: 14 records, May 25 to September 14; 7 records, June 21 to July 20.

New York: 23 records, May 11 to July 18; 12 records, May 29 to June 9.

CUCULUS OPTATUS OPTATUS Gould

HIMALAYAN CUCKOO

Contributed by Edward Charles Stuart Baker

HABITS

The Himalayan cuckoo very closely resembles the various races of the common cuckoo (Cuculus canorus) in its general habits, but it is, I think, a more secretive bird, keeping closely to tall trees with dense foliage, so that although one may hear its very distinctive call on many occasions quite close by it is often very difficult to see until it takes to wing. In Kashmir and the northwest Himalayas it is found in summer at all elevations between 5,000 and 10,000 feet and occasionally to some 2,000 feet higher but, never, I believe, above the forest line. In Sikkim it is common in well-forested land between 4,000 and 9,000 feet, while Stevens (1925) records having heard it calling at an elevation of 3,500 feet on May 25, so that it may breed as low down as this in that part of the Himalayas. In Assam it is very common between the same elevations as in Sikkim, there also keeping closely to forest, either deciduous, pine, or evergreen with dense undergrowth. All ornithologists seem to agree as to the nature of the country frequented by this cuckoo. In letters to me A. E. Jones mentions “dense forest,” “dense deodar forest” as the breeding haunts of birds whose eggs he has found; B. B. Osmaston (MS.) found it in “open, well-wooded forest.” Mackenzie and Hopwood (MS.) took eggs in the nests of Acanthopneuste davisoni in the Chin Hills, in “heavy evergreen forest.” The only exception to this of which I am aware is an egg taken by T. R. Livesey (MS.) found in Kashmir in a nest of Emberiza cia stracheyi in a “well-wooded glade in forest.”

At all seasons of the year it keeps almost entirely to branches of high trees, some 40 or 50 feet or more from the ground, descending to the undergrowth only when hunting for nests in which to deposit its eggs or for the actual deposition of the egg. When so employed it is, I believe, always silent and, even in its movements, very quiet and secretive unless it is being harassed by small birds who hunt it just as they do the common cuckoo. I have not seen this bird feeding in bushes or on the ground even when there are numerous caterpillars or a flight of termites to tempt it.

When on migration also this cuckoo seems to keep to forest or to exceptionally well-wooded country, and I have no record of its having been found in the open in India, though obviously it must sometimes pass over such country in its movements from one district to another, more especially in the northwest.

Spring.—In Kashmir and the northwest Himalayas the birds arrive from the lower hills and the plains adjoining them in April, a few apparently in the first fortnight, but the majority not until the last week or so. In Sikkim they arrive a good deal earlier, and Stevens (1925) records them as seen at Gopaldhara in the Rambong Valley about the middle of March “when it ascends to an elevation of 7,000 feet,” while he heard them calling at the same place as early as March 12. Farther east in Assam it does not arrive at its breeding quarters in the higher hills until about the first week in April and then only in small numbers. In Burma at elevations of about 4,000 feet and over it breeds about a fortnight earlier and is in full call by the last week in March.

This cuckoo is possibly only a partial migrant in India, leaving the higher hills for the broken foothills, where it may be found more or less throughout the winter, as well as in the plains immediately adjoining them. To the east, however, as I show under the fall migration notes, it is a true migrant. According to La Touche (1931–1936), during the spring migration north the Himalayan cuckoo “appears in China from about the 10th April to the end of May,” and he records three cuckoos taken at Shaweishan on May 1, 16, and 17. These birds were presumably on their way north to eastern Siberia or Manchuria.

La Touche does not think that this bird breeds anywhere in the Chinese Hills, its place being taken by the local breeding race kelungensis.

The 38 eggs in my collection were taken as follows: Three in April, 14 in May, 20 in June, none in July, and 1 in August. The earliest date was April 25, 1915, and the latest August 20, 1914. At the same time an egg taken in the Chin Hills on April 30 was on the point of hatching, so, in the Burmese Hills, some eggs must be laid in the middle of that month, birds arriving in their breeding haunts at least a fortnight earlier. Other eggs that have passed through my hands were all taken within these dates so far as I have recorded them, so they may be accepted as confirming my dates for migration.

Courtship.—There is nothing recorded upon this subject but, so far as I know, it differs in no way from that of the Khasia Hills cuckoo, and both sexes seem to be equally promiscuous in their sexual relations.

Nesting.—This cuckoo is parasitic principally on the small warblers of the Phylloscopus and Acanthopneuste group, which lay white eggs, either immaculate or speckled slightly with various tints of reddish brown or red, or the Seicercus group, which lay glossy pure white eggs.

In my own collection I have eggs taken from the nests of 16 species and subspecies of fosterers (see the following list); of these the first 10 may be considered to be normal fosterers and the latter abnormal.

The Himalayan cuckoo does adopt a certain territory but hardly in the restricted sense that Cuculus canorus and its various races do. The principal reason for this is the comparative rarity of the birds that she selects as foster parents to her eggs. For instance, although the little Acanthopneuste breeding in the Khasia Hills is a common bird, it nowhere breeds in the numbers in which birds of the Suya and Cisticola genera are found. Perhaps half a dozen pairs may be found in one big forest of many square miles, and to find even these six is very hard work. In the same forest another half dozen birds of the genus Seicercus of various species may be found. These little warblers of the two genera Acanthopneuste and Seicercus make very similar nests, balls of moss, quite green and fresh, which are placed in hollows in banks and generally among the same kind of moss as that of which the nests are built. They are exceedingly hard to find by human beings and, unless the birds are watched on to the nest, are generally located only when the female is disturbed from it by accident and doubtless the cuckoo also finds they are difficult to mark down.

List of Foster Parents eggs

Phylloscopus inornatus humei 2

Phylloscopus proregulus simlaae 1

Acanthopneuste reguloides harterti 13

Acanthopneuste reguloides davisoni 3

Acanthopneuste reguloides reguloides 1

Acanthopneuste occipitatis occipitatis 4

Seicercus cantator 3

Seicercus burkii 2

Seicercus xanthoschista xanthoschista 1

Seicercus castaneiceps castaneiceps 2

Ianthia rufilata 1

Niltava sundara sundara 1

Suya crinigera assamica 1

Orthotomus atrogularis nitidus 1

Napothera brevicaudata striata 1

Emberiza cia stracheyi 1

I have only two small series of three eggs, each of which I believe to have been laid by one cuckoo, one of these being taken in 1909 by myself. Of this latter the first two eggs were found on June 16 and 18 in a patch of forest in which we marked down three nests of the Khasia crowned willow warbler, one of which contained no cuckoo’s egg. On June 13 we found that the pair of warblers first seen on May 16 had again built close by their original nest and the new one contained a third egg, apparently of the same cuckoo, and three of their own. The nests found on May 16 and 18 were between a quarter and a half of a mile apart.

On another occasion, June 27, 1935, three eggs were taken, one in the nest of the willow warbler and two others in nests of Seicercus. These were all in the same forest, but only two close together and the third nearly half a mile away. The eggs, however, appeared obviously to have been laid by the same bird.

Eggs.—The eggs of this species of cuckoo are all of the same type, white eggs sparsely marked with tiny black specks, sometimes confined to the larger end only. Several oviduct eggs have been taken, the first by Brooks from the oviduct of a female he shot in Kashmir on June 17, and three others by Rattray in 1903 on June 10, 15, and 17, respectively. All these were exactly alike and similar to the description given above.

The only two exceptions in coloration I have seen are eggs one of which has a faintly green tinge while the other has an equally faint pink tinge. The first of these was taken from a forktail’s (Enicurus maculatus guttatus) nest and the second from that of a tailorbird (Orthotomus atrogularis nitidus).

In shape the eggs are rather long ellipses, and the shell is thin and rather fragile for a cuckoo’s.

Forty-one eggs average in size 20.11 by 14.28 millimeters; maxima 25.3 by 16.2; minima 19.0 by 13.0 millimeters; the same number average in weight 141.4 milligrams; maximum 178; minimum 117 milligrams.

A large double-yolked egg weighs 222 milligrams, while two very small, almost pygmy eggs, weigh only 105 and 112 milligrams.

The method of the deposition of the eggs is not known, but in many cases they could not possibly be laid direct into the nest. The crowned willow warbler makes a nest in a hole in among the roots of trees with so small an entrance and so far in that the cuckoo could not possibly get in to lay her egg nor could she eject it from the cloaca sufficiently far to reach the egg chamber and, if she did, it would certainly break. Nests of the genus Seicercus and of Acanthopneuste reguloides are so shaped and situated that though the cuckoo could not enter them she could very often eject the eggs into them without much difficulty by clinging to their tops or sides during the operation.

Young.—Nothing is recorded, as to incubation, but I believe it to take only 10 or 11 days, i. e., much the same period as for the eggs of the small warblers the cuckoo selects to cuckold.

Ejection of young undoubtedly takes place in the same manner as that by which it is effected by the common cuckoo, the young cuckoo hoisting the other occupants of the nest, either eggs or young birds, onto its shoulder and then pushing them over the edge of the nest. I have seen several young birds from two days to a week old in the nests of various warblers, and they have always been alone. The young cuckoo has the same dorsal interscapular arrangement as that found in the nestling canorus to assist it in carrying out the fratricide.

Plumages.—Male: Similar to the male of Cuculus c. canorus and C. c. bakeri but less dark on the upper parts than the latter and always to be distinguished from all races of the canorus group by having the edge of the wing pure white and not barred. On the lower surface the white bars are broader and the black bars in consequence wider apart, while they are blacker and bolder in appearance.

Female: Similar to the male but generally with a more rufous tinge on the breast and abdomen; the under tail coverts are often pale fulvous with black crossbars.

The female has a hepatic phase like that of C. c. canorus.

Juvenile: In first plumage blackish brown above, the feathers all broadly edged with white; the wing quills are barred with rufous on the outer webs; the chin, throat, and breast are blackish, the feathers narrowly fringed with white and the rest of the lower parts white, or faintly fulvous-white, heavily barred with strong bands of black.

In intermediate stage between juvenile and adult the plumage is slaty, the feathers very narrowly edged with white; below, the chin, throat, and upper breast are blackish, the feathers broadly fringed with white and the remainder of the lower parts like the adult.

Hepatic young are like the hepatic female adult but less richly colored and more heavily banded below with blackish, especially on the chin, throat, and breast. Some specimens of young birds in the British Museum collection seem to be changing from a juvenile hepatic plumage into a normal adult plumage.

The white nuchal spot is very seldom seen in the young of this cuckoo but is occasionally present.

Measurements.—Wing 208 to 226; tail 151 to 176; tarsus about 20 or 21; culmen 20 to 22 millimeters. The female is little, if any, smaller than the male in Indian birds, but of Chinese birds La Touche gives the following measurements: Male, 23 (2 examples), wing 200 to 226; female, 22 (1 example), 190–200; culmen, male, 20–22; female, 19 millimeters.

Colors of soft parts.—Iris yellow or “grey with brown inner circle” (La Touche); bill dark horny green, the base of the upper, and most of the lower, mandible yellowish horny, the gape still more yellow; legs and feet wax-yellow to rather bright yellow.

Food.—This also is the same in character as that of Cuculus canorus, but C. optatus also devours more hard-bodied insects such as Cicadae and many small and some quite large beetles, while it feeds rather more exclusively on food obtained near the tops of high trees. I have never seen it feeding on the ground, nor have I noticed it in scrub or bushes except when it was probably hunting for a nest in which to deposit its egg.

Behavior.—I do not think that this bird could be distinguished from Cuculus canorus, except by its voice, by any field naturalist until the bird was actually in his hand. In flight, perching position, and general action I have been able to discern no difference of any kind between the two birds unless it is that when the two were seen together optatus looks a smaller, slighter bird than canorus and may fly a trifle faster with quicker wing beats.

Both sexes have the habit, as canorus has, of sitting, almost motionless, for a very long time in one position, possibly in the case of the female while she is watching certain birds and waiting for them to give away the site of their nest, or when she is waiting for the precise moment at which to fly down and place her egg in the nest of the foster parent selected to receive it.

Voice.—The call of the male consists of four notes, two rapid, then a pause, and then two more, all of the same cadence, sounding like hoo-hoo hoo-hoo. When one is close to the bird a fifth note can be heard preceding these, much higher pitched and far less resounding so that at a little distance only the four notes are heard. The call is a typical cuckoo note, and hearing it one would expect to find that a cuckoo had uttered it. There is also a sweet trilling note that is rarely heard, and I cannot say whether it is uttered by one sex or both, but I suspect it to correspond to the bubbling note uttered by the female canorus. Although occasionally this cuckoo calls on moonlight nights it does not do so with anything like the perseverance of the common cuckoo, nor is it so incessantly vocal during the day.

Enemies.—The same as those of the common cuckoo, but the young do not suffer so much from exposure by falling out of nests too small or too weak to hold them. In the case, however, of eggs laid in holes occupied by the nests of the crowned willow warbler the young birds have to vacate them at a very early stage or they would be unable to do so when full grown and would be incarcerated in them for life. As these cuckoos select ground nests so largely in which to deposit their eggs, these and the young birds when hatched do not suffer so greatly from the crows and magpies who hunt the hedges and bushes, but, on the other hand, they are easier for snakes and lizards to get at.

Fall.—Migration from the breeding grounds in northwest India apparently commences in the end of August and continues to the end of September or early October. From northeast India they would seem to migrate later by about a month, birds continuing to call up to the beginning of August, while in 1914 an egg was taken as late as August 20. It is a curious fact that in the continent of India birds do not seem to move far south and have only been recorded in winter from many places in the plains of the northwest and Punjab and from Lucknow, Jodhpore, Fategarh, Bihar, Dibrugarh and Cachar, in the United Provinces, Bengal, and Assam. Farther east it migrates much farther south and has been recorded from all over Burma to the extreme south, and from the Andamans and Nicobars, while it also ranges throughout the Malay Peninsula and the Austro-Malaysian islands to New Guinea and Australia. Birds found in winter east of Burma are certainly those that breed north of China and probably migrate, more or less, due north and south, and I am inclined to think it is possible that birds from the Himalayas migrate almost entirely to the east in India and then southeast through Burma and the Malay States. Otherwise it seems incredible that no specimens should ever be obtained, in south India or even central India, of a migrant which in and from China wanders so very far south in the winter months.

DISTRIBUTION

The Himalyan cuckoo is found throughout the Himalayas and central Asia from the extreme west of India and Baluchistan, while in central Siberia it extends from Dauria and Lake Baikal to the extreme east of the northern Chinese mountains and, possibly, to Japan. In China La Touche (1931) summarizes its distribution as follows: “China generally, Szechuen, Kwangsi, Fohkien, Lower Yangtse, Shaweishan, Shantung, Chihli (migrant).” To this he adds, “On the whole this Cuckoo is not common in North China, and very few have been noted by Dr. Wilder,” and, again, noting on my distribution of the summer range he adds, “Corea and Manchuria should probably be added.”

It certainly occurs and breeds in all the higher hills in Burma; quite commonly in the Chin Hills and rarely to the east in the Ruby Mines district and the Shan States.

Its appearance on the American list is due to a specimen obtained on St. Paul Island, Pribilof Islands, Alaska, on July 4, 1890 (W. Palmer, 1894).

CUCULUS CANORUS BAKERI Hartert

KHASIA HILLS CUCKOO

Contributed by Edward Charles Stuart Baker

HABITS

This most interesting race of the common European cuckoo was given a name in 1912 by Dr. Hartert (1912), no museum possessing sufficient material until 1911 to substantiate the differences that both Dr. Hartert and I believed to distinguish this subspecies from those others already accepted.

The Khasia Hills cuckoo is a race that breeds at considerably lower elevations than do either C. c. canorus or C. c. telephonus and, speaking generally, haunts during the breeding season more densely forested areas in much hotter and far more humid climates. Thus in the Khasia Hills of Assam, where it is extraordinarily common, it may be found in all the higher ranges at and about Sherraponji between 3,500 and 6,500 feet frequenting forest that is always lush and green, with luxuriant undergrowth and with an almost impenetrable tangle of creepers, beautiful orchids, ferns, and parasites growing on every tree. Here the rainfall averages about 550 inches in the year, while as much as 72 inches have fallen in 24 hours and over 700 inches in the 12 months. They are, however, equally numerous, between 4,000 and 6,000 feet around Shillong, where the rainfall is less than 150 inches in the year and where, in many parts, pine woods take the place of the wet evergreen forests.

Although on the whole this race of the cuckoo certainly frequents denser and thicker forest than do the other forms, individuals vary greatly in their tastes and those parasitic on pipits and other species of birds, which breed in the open grass plains, also haunt the same kind of country as that in which these birds breed. At the same time even in these places they always select those that contain a certain number of trees on which they can perch and from which they can survey the surrounding area and watch the fosterers to their nests. In the Khasia Hills many cuckoos are parasitic on the common Indian and Blyth’s pipits, which are to be found nesting on the wide stretches of open grassland above Shillong, the former on ridges and plateaus up to some 5,500 feet and the latter on those above that altitude. Intermediate in habits between the evergreen forest cuckoos and the open country cuckoos there are others that haunt the more open pine forests, especially those that have brooks and small rivers running through them, or are broken up by ravines in which small deciduous trees, bushes, and brambles grow freely to the exclusion of the somber pine trees.

In Burma this cuckoo is commoner in the Ruby Mines district and in the Southern Shan States than anywhere else. T. R. Livesey, who has had a wonderful experience with them in the latter country, informs me that in these districts they frequent both the open deciduous forests as well as the open country of scrub and grass land around towns and villages, even depositing their eggs in the nests of birds breeding in and close to the gardens of houses occupied by Europeans or by Shans.

After the breeding season this cuckoo may be found in almost any kind of country that is fairly well-wooded, while in the plains of Bengal and Lower Assam it seems to have a special liking for mango orchards and patches of jungles in tea plantations.

Spring.—In Assam those individuals that have migrated into the plains and lower hills the preceding autumn return to their breeding quarters in the end of March or early April, their numbers increasing rapidly up to the end of that month, when their mellow call may be heard almost continually in every direction at all elevations between 3,500 and 6,500 feet. Exact dates of arrival are recorded nowhere that I can trace, but I have eggs taken on April 14, odd eggs taken in the third week in April, and many after the 25th of that month.

In the Chin Hills, between Assam and the Ruby Mines district and Shan States, most cuckoos commence breeding about the middle of April, arriving in their breeding haunts nearly a month earlier. Here they are common at about 4,000 feet upward and haunt much the same kinds of country as they do in Assam, certainly breeding up to 7,000 feet, or a little over, as eggs have been taken on Mount Victoria and the hills above Fort White.

In the Shan States Mr. Livesey informs me that few if any birds remain above 4,000 feet in winter, in the end of August and early September the great majority moving into the lower hills and adjoining plains. The first birds returning to the higher hills put in an appearance early in March and commence to lay the last of that month, March 27 being the earliest date on which he has taken eggs and July 1 the latest.

The length of the breeding season is much more extended than is that of the European cuckoo (C. c. canorus) or the central Asian bird (C. c. telephonus), doubtless owing to the same factors of cold, food supply, etc., that compel the more northern birds of all families to compress their breeding arrangements into a far shorter time than that occupied by the southern birds, for whom temperature, food supply, and other factors are more or less favorable almost throughout the year.

The individual cuckoo, however, is governed in her time of egg-laying by the habits of the foster parent that she selects to bring up her young, while all cuckoos, as well as the foster parents, are affected more or less in their spring migration and breeding time by the late or early arrival of the rains and the consequent shortage or abundance of insect life. In Assam, where the rainy season is long and the rainfall heavy, eggs may be found in some numbers from April 20 to the middle of June and, then, in decreasing numbers, to the end of June, after which they further decrease in number until, after the middle of July, few will be taken, though my latest recorded date for a cuckoo’s egg is August 24. In Burma, as already noted, birds commence laying about a month earlier, and few eggs are found after early June.

The 1,366 eggs in my collection were taken as follows: One in March (taken in Burma), 104 in April, 608 in May, 527 in June, 114 in July, and 12 in August. It may, I think, be accepted that migrating birds arrive on their breeding ground some two to three weeks before commencing to lay and leave again about one to two months after the deposition of their last eggs.

In Burma the peak of laying is reached in early May; in Assam not until the end of that month.

Courtship.—I can find nothing recorded as to the conduct of courtship between males and females during the breeding season and have, therefore, only my own observations to guide me. There appears to be no true courtship, and I have no doubt that, except in very rare instances, cuckoos do not pair, though in certain areas, where the bird is uncommon, a male and female may possibly mate and remain together throughout the breeding season. This is probably the case in North Cachar, where the bird is rare, breeding in deeper forest than I have seen anywhere else, and where I have seldom heard more than one male calling in any one particular area or found more than one type of egg deposited therein. In the Khasia Hills, in which district the birds swarm in incredible numbers, both sexes were undoubtedly promiscuous in their sexual relations. I have personally seen a female accept the attentions of one male and then fly off to a tree close by and accept another pursuing male within a few minutes. On this occasion several, I think four, males were pursuing the one female, who flew slowly from one tree to another on a roadside. Settling on one of these she crouched on a large bough, half lying there with both wings hanging slightly lowered and quivering, while her head was held quite low, her whole attitude expressing invitation. The first male, of those following her, at once accepted this after which he settled on a branch close by while the female flew away to a tree about 50 paces distant followed by the other three males, one of whom was again accepted by the female who, after the completion of the act flew off accompanied by the remaining two males to a tree beyond my view.

Among the Khasias, certain classes of whom are very intelligent observers, it appears to be well known that both sexes of cuckoo exercise no discretion in their love affairs.

Nesting.—The female cuckoo is, of course, parasitic in her habits, and I have personally taken eggs in the nests of no less than 103 species and subspecies of fosterer (see following list), the very great majority of which are, however, undoubtedly abnormal or casual only, for I feel satisfied that when the usual foster parent has no nest available the cuckoo will eventually deposit her egg in that of any other bird that may be convenient. Repeated instances have come within my own experience in which a cuckoo normally parasitic on one bird deposits one or more of a series of eggs in a nest utterly unlike those of the usual fosterer, merely because she has already exhausted all the nests known to her of the latter.

List of Foster Parents eggs

Suya crinigera (subspecies 6) 215

Cisticola jundicis cursitans 276

Cisticola exilis tytleri (generally with C. j. c. series) 7

Tribura luteiventris 32

Orthotomus (species and subspecies 2) 27

Acanthopneuste reguloides harterti 9

Megalurus palustris 7

Miscellaneous warblers (abnormal fosterers, 9) 25

Anthus (various species and subspecies, 8) 199

Rhodophila ferrea haringtoni 18

Saxicola caprata burmanica 55

Rhyacornis fuliginosus 25

Enicurus (species 2) 25

Petrophila (Monticola) (species 2) 21

Turdidae (abnormal fosterers, species 8) 15

Cyanosylvia leucura 13

Eumyias thalassina thalassina 63

Niltava (species 3) 43

Muscicapidae (abnormal fosterers, species 12) 22

Lanius nigriceps nigriceps 35

Laniidae (abnormal fosterers, species 2) 2

Troglodytidae (species 3) 21

Mesia agentauris 46

Leiothrix calipyga 33

Timaliidae (abnormal fosterers, species 32) 92

Other abnormal fosterers, Passer, Sitta, Parus, etc. (7 species) 8

Total Fosterers: Normal 23, abnormal 80 ( = 103).

Like the English cuckoo, as Chance (1922) has proved, the Khasia Hills female cuckoo sometimes adopts a certain area of country as its own breeding territory into which it will allow no other female, parasitic on the same foster parent, to enter, though it seems to have no objection to the entry of any number of males or of another female parasitic on a different species. Thus in a certain area close to the house in which I lived in Shillong I found three cuckoos breeding; one depositing its eggs in the nests of the little fantail warbler (Cisticola juncidis cursitans), the second in the nests of the verditer flycatcher (Eumyias thalassina thalassina), and the third in the nests of the black-headed shrike (Lanius nigriceps nigriceps). On another occasion I took eggs of three different cuckoos from nests of Cisticola, Niltava, and Leiothrix in the same strip of jungle and not 50 yards from one another. Yet another instance of shared territory was a grass-covered hillside occupied by two female cuckoos, the one parasitic on the same little fantail warbler and the other on pipits (species various). Other similar instances were quite common in this district.

My personal experience confirms what those interested in cuckoo-work have for some time maintained in regard to cuckoos being consistently parasitic on one selected foster parent. A good example of this constancy is a series, collected for me by a family of four men trained by myself in cuckoo-work in the Khasia Hills. From 1925 to 1935 these men obtained for me no less than 132 eggs of one cuckoo parasitic on the fantail warbler, all collected in the same area of grass and scrub surrounded by pine forest. Of these 132 eggs only 4 were taken from nests other than those of the little fantail and of these 4, 3 were placed in the nests of another little warbler (Orthotomus sutorius patia) and the other in the nest of the Assam brown hill warbler (Suya crinigera assamica), both, of course, in the same territory.

In addition to the above I have many series of eggs, numbering 3 to 15, from individual cuckoos, occasionally taken in two or more consecutive years, all placed in nests of the same warbler. Again I have other series of cuckoos’ eggs, some taken from nests of Suya (various species); others from those of Eumyias, pipits (various species), the silver-eared mesia (Mesia a. argentauris), the Pekin robin (Leiothrix lutea calipyga), and other fosterers. As a rule the cuckoo also shows equal constancy to its chosen breeding area, returning year after year to it and leaving it only when the supply of fosterers is exhausted or the nature of the country has been altered by man or some other agency. Where the normal foster parent is exceptionally common, such as are the warblers of the genera Cisticola and Suya, the cuckoo often has ample nests in a compact area to act as hosts to her whole series of eggs, and we have found as many as 18 eggs laid by the same individual within such an area. Where, however, the fosterers such as pipits or mesia are less numerous or are breeding in comparatively small areas, some 4 to 10 eggs are laid in the one area and then, when the available nests have all been made use of, the cuckoo removes to another area, generally close by, eventually often returning to the original one later in the season and again cuckolding other nests of the same fosterer.

There can, I think, be no doubt that a cuckoo brought up in a nest of a certain fosterer will deposit its own eggs in nests of the same bird. This theory seems now to be one generally accepted, and certainly my experience goes to confirm this, and in my own collection I have eggs of a very definite type taken for over 30 years in the nests of the same species of fosterer in the same district.

Eggs.—The eggs of the Khasia Hills cuckoo are of very many and beautiful types of color and character of markings, while the eggs of each individual cuckoo, though varying slightly inter se, do not show so great a variation as is found in the eggs of single clutches laid by many species of Passeres or other orders.

Among the most common types of eggs are, naturally, those that have been evolved to assimilate with the eggs of the birds most frequently employed as foster parents. Among these may be mentioned the following:

An egg with a white ground lightly marked, chiefly at the larger end, with specks, spots, or small blotches of red, reddish brown, or brown. These eggs are excellent counterparts in all but size of the eggs of the fantail warbler, in whose tiny nest they are usually deposited.

The next commonest type has the ground color more or less distinctly tinged with reddish and is rather more profusely marked with larger blotches of various shades of red-brown. These are normally deposited in the nests of various species of Suya, or brown hill warbler, the most common types of whose eggs agree well with those of the cuckoo.

A third and common type of cuckoo’s egg has the ground color a beautiful salmon-pink or buff-pink and has the surface freckled with deeper reddish; in some cases so finely and thickly that the eggs appear at first glance to be unicolored; in other cases more or less boldly, though sparsely, covered with reddish brown and underlying faint marks of gray or pale purple. These eggs agree well with various types of eggs laid by the verditer flycatcher and, even still more so, with those of the beautiful niltava (Niltava sundara), while it is in the nests of these birds we find them deposited. Cuckoos, however, that normally deposit their eggs in the nest of these birds seem regularly also to cuckold the large niltava (N. grandis) and the white-tailed chat (Muscisylvia notodela), which lay the same colored eggs and make similar cup-shaped nests of living moss, built in exactly similar positions in holes in banks and among boulders.

Another beautiful type is bright pale blue, often immaculate but sometimes faintly flecked with primary reddish and secondary gray blotches. In the Khasia Hills these are almost invariably deposited in the nests of the silver-eared Mesia or the red-billed Leiothrix (L. lutea calypga), two species that lay exactly the same type of egg to that of the cuckoo, though more boldly blotched, while the two species also make similar nests, which they place in somewhat similar positions in bushes, etc.

In Burma, more especially in the Ruby Mines district and in the Shan States, we have two dominant types of eggs: One blue, much darker in tint than those referred to as being deposited in Leiothrix nests, laid with the similar eggs of the Burmese dark gray bushchat (Rhodophila ferrea haringtoni), and the other having a pale pink ground, freely blotched all over with reddish, deposited in the nests of the Burmese stonechat (Saxicola caprata burmanica), which also lays eggs of this color and character. In connection with these two types of egg an interesting state of affairs has now been arrived at in parts of the Shan States. Thirty years ago the bushchat was extremely common in certain districts in hills between 4,000 and 5,000 feet, and the great majority of cuckoos found there were those laying blue eggs. Cultivation has now wiped out the scrub and bush jungle, beloved by the bushchat, and fields of rice, gardens, and the vegetation surrounding villages have taken its place. With this change in the character of the jungle growth has also come a change in the birds frequenting it, the bushchat has almost disappeared, and the little stonechat has taken its place, breeding everywhere in gardens, village grounds, and cultivated fields. The elimination of the bushchat, although so recent, has already gone far to eliminate also the cuckoo that lays blue eggs, while the one that lays eggs like those of the stonechat has become much more numerous and has become the common form. Even now, however, an occasional blue egg of a cuckoo will be found in the stonechats’ nests, the latter similar in every respect to the nests of the bushchat and therefore cuckolded, faute de mieux, by the cuckoo.