PLATE 2 
EXPLAXATION OF FIGURES 
5 Cuckoo giving feeding reaction shortly after birth, before association with 
nest and parent has been formed, showing peculiar pattern of white pads on palate 
and tongue. Same bird shown in figs. 2 and 3, and photographed on same date, at 
same time, and in nearly the same relative size. Rudimentary down feather-tubes 
of back erect. 
6 Young cuckoo in typical 'quill stage," showing toes clenched, and "flagel- 
late" feather-tubes of contour feathers, before any have been released by the 
combing process. Bird no. 1, nest no. 1, July 25, 4.1.5 p. m; combed off feather- 
tubes, and left nest the night or morning following before 0.10 a. ni. One-half 
natural size. 
7 Contents of nest no. 1; July 23, 11 a. ni. (table 6), showing birds nos. 1, 2, 
and 3, and egg (no. 4). Only the smallest bird, which was but a few hours old, 
would give the feeding reaction, when all were removed from the nest. This bird 
reacted promptly at a given stimulus for the space of twenty minutes. One half 
life-size. 
8 Cuckoo in typical climbing stage, shortly after leaving nest. Bird no. 2, 
nest no. 2, Aug. 10, 9.30 a. m. This bird was in the quill stage (fig. 6) at 6 p. m. 
the day before. Feather-tubes on liead and neck not yet fully released; wing-quills 
free for one half their length; one tail-quill only broken at tip. Bird no. 1 (11 
days old), seen at the same time, but though unable to fly, it could not be captured 
