Note 13 — Chapter II · OXFORD: SPRING AND EARLY SUMMER.
Reading edition
The three species were the Wood-warbler, Phylloscopus sibilatrix (Bechst.), Willow-warbler, Ph. trochilus (Linn.), and Chiff-chaff, Ph. collybita (Viell.). Markwick declares that he could not distinguish the first of these from the other two.