Note 176 — Chapter X

It is worth while to observe, as bearing on this theory of the origin of this parasitic habit, that even non-parasitic birds occasionally deposit their eggs in nests of other birds. Thus, Professor A. Newton writes in his admirable essay on 'Birds' in the Encyclopædia Britannica, 'Certain it is that some birds, whether by mistake or stupidity, do not unfrequently lay their eggs in the nests of others. It is within the knowledge of many that pheasants' eggs and partridges' eggs are often laid in the same nest; and it is within the knowledge of the writer that gulls' eggs have been found in the nests of eider-ducks, and vice versâ; that a redstart and a pied flycatcher will lay their eggs in the same convenient hole—the forest being rather deficient in such accommodation; that an owl and a duck will resort to the same nest-hole, set up by the scheming woodman for his own advantage; and that the starling, which constantly dispossesses the green woodpecker, sometimes discovers that the rightful heir of the domicile has to be brought up by the intruding tenant.'