LIFE AND BEHAVIOR OF THE CUCKOO 
195 
vious nights. The first of these nests contained eggs, and the 
last two recently hatched young.^^ 
The nests of the black-bill are commonly placed at a height of 
4 to 5 feet from the ground, but have been found as high as 18 
feet, and as low as 25 inches (nest no. 2, fig. 9). They are essen- 
tially shallow, saucer-shaped platforms, or concave floorings of 
coarse twigs, leaves and catkins, of rather greater bulk and better 
construction than in the case of the yellow-bill, and are usually 
well concealed and protected from the wind. At Northfield, N. 
H., we have found them only in saplings of the white pine, and 
in thorn and wild apple bushes. The act of nest-construction has 
not been witnessed, but presumably both sexes take part, as is 
often the case when, as in the present instance, both share in 
incubation and in the care of the young. One of these nests 
which was particularly examined had an inner diameter of 4 inches 
and an inner depth of i inch, the greatest diameter being 7 inches, 
and total height 2J inches. It consisted of a scant foundation 
of old brake-leaves, interstratified with coarse twigs, and sur- 
mounted with finer twigs and a topping of pine needles, dead leaves 
of the birch, brake, and willow catkins. Another nest of the sea- 
son, examined on June 28th, contained the shell of the last egg 
hatched, and had essentially the same structure, with the addi- 
tion of pulled grass, and a larger mass of willow catkins, which 
formed about one-half of the nest materials. I estimated the 
whole to represent about 150 loads, brought in the bill of one or 
both birds. Further, judging from the form and symmetry of 
these nests, the cuckoo practises instinctively both the molding 
and turning movements, so marked in all species with typical 
cup-shaped inner walls, though in this case with very meager re- 
sults. 
The eggs (v. table 2 and fig. 1) are nearly oval; they have thin 
fine-grained shells, and according to Bendire, vary in color from 
nile blue to pale beryl green; very rarely an egg is marbled, 
''caused by different shades running into each other," an illus- 
" Bendire, Charles. Life histories of North American birds. Smithsonian 
contrib., vol. 32, p. 29. Washington, 1895. 
