%1GGS: 
Tlie number of egg's laid during the season seems to vary considerably. If the mother bird begins 
incubation as soon as the first egg is deposited, as many as six or eight may be dropped during the 
sitting, at intervals of two to five days. In which instance young birds of different ages, and fresh and 
partly incubated eggs, to the number of eight, may be in one nest. But when incubation does not begin 
until the complement is completed, as is commonly the case, four eggs, rarely six, make up the set. 
The color of the eggs when recently blown is light bluish-green, varying a little in shade in different 
specimens. The shell, which is never glossy, is sometimes mottled with darker shades of the same 
color, or mottled or specked with white. The size and shape is by no means constant, even of eggs 
from the same set; some are elliptical, others are quite pointed at one end, and still others are irregular 
in outline. The average size of twenty-eight specimens is 1.27 x .89. The smallest, 1.13 x .85 ; tlie 
largest, 1.33 x .97. 
DIFFERENTIAL POINTS : 
See page 45. 
REMARKS : 
The nest illustrated was taken on the twenty-eighth day of May, 1878, from a black-haw. The 
branches upon which the nest rested were inclined at an angle of 45°. The plate shows the branches 
in a perpendicular position, the nest being thus inclined sufficiently to give a view of the upper surface. 
The materials of construction are sticks and catkins of the oak. The dried leaves belong to the 
dead branch which is lodged in the fork. In six days after its completion four eggs had been deposited, 
and incubation had commenced. The eggs figured show the common shapes, shades of color, and irregu- 
larities of outline. They are colored from freshly blown specimens. 
The habits of our two Cuckoos are so similar as regards locality, position, and materials for ncst- 
buildmg, and even the eggs are often so much alike, that it may be of value to some to mention a 
peculiarity of plumage which will always determine the species if any doubt exists. In collecting, it is 
not always possible to examine closely the bird when the nest has been found. She may, if upon the 
nest, sit closely any desired length of time, and permit a thorough inspection at a reasonable distance ; 
but usually, just as careful notes of bill, eye, and general plumage arc being made, the bird silently 
glides, almost drops, from the nest into the thicket, and cither patient waiting must be endured or 
another visit made, for it is almost impossible to procure a view of her after she has gained the foliage. 
But the trouble of waiting, or another visit, will not be necessary if attention is given to the marking 
of the tail-feathers as the bird flushes from the eggs. If large blotches of white are seen, it is C. ameri- 
canus. If no white appears, or only a very little about the tips of the feathers, it is C. enjthrojjthalmus. 
So conspicuous are these white spots on the tail-feathers of the former, that they may always be seen 
if looked for, though the bird is visible but for an instant, and that in the densest cover. As a rule, 
the best way to identify the species when found sitting, is to frighten the bird from the nest and observe 
the tail-feathers as -she flies away. 
The character of the Yellow-billed Cuckoo is not above suspicion. In fact it was long ago convicted 
of theft and murder, though perhaps not quite so blood-thirsty as the Blue Jay. The female has, to 
some extent the indolent habit of the Cow Bunting and European Cuckoo. I once found an egg in the 
nest of the Cardinal Grosbeak, and once in a Catbird’s nest; the latter may possibly have been the 
property of the Black-billed, but about the former there was no doubt. 
70 
