YELLOW-BILLED CUCKOO 57 



Flying Into an adjacent apple tree containing a considerable quantity of dead 

 material, the Cuckoo landed on a limb, selected a dead twig, and grasping it 

 in her bill bent it back and forth until it snapped from the limb, whereupon 

 she flew with it to her nesting-site in the next tree, arranged this twig and 

 quickly returned for another. As she tugged at a stubborn twig, her back was 

 arched and her long tail curved under or waved about. If a twig resisted too 

 well her attack, the bird desisted at once and tried another. Always she 

 worked rapidly with great energy, attacking a twig as soon as .she landed in 

 the tree, never carrying more than one twig at a time, holding it squarely at 

 right angles to her bill and flying rapidly with long tail streaming. 



The Cuckoo's concentration in the work, coupled with her indifference to ob- 

 servers, was remarkable. Not once did she descend to the ground for material. 

 Not once did she gather material in the tree in which her nest was located. 

 With two exceptions the twigs were all gathered from the same tree. Working 

 thus off and on for an hour or two at a time, the bird completed the nest. 

 The third night the Cuckoo was sitting on the nest at dusk, but after two days 

 she deserted. 



Eggs. — The yellow-billed ciickoo lays ordinarily three or four eggs, 

 sometimes only one and rarely five; as many as six, seven, or even 

 eight eggs have been found in a nest, but these larger numbers may 

 be the product of more than one female. The eggs vary in shape 

 from elliptical-oval to oval, oftener nearer the former, and about 

 equally rounded at both ends. The shell is smooth, but without 

 gloss. Bendire (185)5) says that the "color varies from a uniform 

 Nile blue to pale greenish blue when fresh, fading out in time to a 

 pale greenish yellow." Eggs that I have examined in collections vary 

 in color from "pale glaucous green" to "pale fluorite green." The 

 measurements of 53 eggs average 30.4 by 23 millimeters; the eggs 

 showing the four extremes measure 34.64 by 23.11, 33.53 by 25.40, 

 27.43 by 22.86, and 29.21 by 20.83 millimeters. 



Young. — The period of incubation is said to be about 14 days; it is 

 shared to some extent by both sexes, but is probably performed 

 mainly by the female. The eggs are sometimes laid on succeeding 

 days, but oftener at more or less infrequent intervals; the young, 

 therefore, frequently hatch at irregular intervals, and young of differ- 

 ent ages are often found in the nest. 



Snyder and Logier (1931) say of a brood of young that they ex- 

 amined: "The young were quite active when disturbed. They 

 scrambled about the bush, using the wings and bill for climbing. 

 One young which was brought to our camp demonstrated a remark- 

 able reptile-like behaviour. When it was placed on the table and one 

 reached to pick it up, it erected its somewhat horny plumage and 

 emitted a buzzing hiss like the sound of bees escaping from a tunnel 

 in dry grass. This performance was certainly unbirdlike in all re- 

 spects." 



Francis H. Allen writes to me: "I found a young one in an open 

 field on the ground. I was attracted to the spot by its loud rasping 



178223—40 5 



