Plate LIV. 
Fig 3. MOLOTHRUS ATER-Cowbird. 
Cowliirds arrive about the middle of March and remain until November, with the exception of a 
few weeks in July and August, during which time they disappear. Dr. Wheaton has seen them at this 
season in the mountains of Pennsylvania, but “where they go, and what they do, has never been cer- 
tainly discovered.” ' 
At the present time the Cowbird is a very common species, but as late as 1853 it was by no means 
numerous, and Dr. Kirtland admitted it to the fauna of the state on “rather doubtful authority.” 
EGGS: 
The eggs of the Cowbird measure in long-diameter from .78 to .90, and in short-diameter from .60 
to .66. Ten eggs, selected from about one hundred specimens, measure as follows: ,78x.65, .81 x .66, 
.82 x .65, ,83x.63, .86 x .66, .87 x .64, .87 x .66, ,86.x .-61, .90x.64, .90 x .65. The ground-color of the shell 
is white, but sometimes it is obscured by the abundance of the markings. These generally consist of spots 
and speckles, distributed pretty evenly over the entire shell, together with blotches which are the most numer- 
ous about the base, and commonly confluent with the spots and speckles. The speckles predominate on 
most eggs. Occasionally, an egg is marked almost entirely with irregular spots of about the area of a 
pin’s head. The color of the markings is very uniform, being brown inclined to yellow; sometimes it is 
pretty deep in tint, but usually it is rather faded in appearance. The deep shell-marks, which are fre- 
quently quite numerous, have a faded, bluish cast. 
DIFFERENTIAL POINTS : 
When the egg of the Cowbird resembles so closely the eggs in the nest where it has been laid, as 
to make identification uncertain, it is a good plan to blow all the eggs and notice if the suspected egg 
has a yelk of different tint from the balance of the set. If it has, it is strong evidence that it was laid 
by some intruder, for almost invariably eggs of the same set have the same tinted yelks. 
REMARKS : 
The Cowbird does not build a nest, preferring to deposit her eggs in the nests of other birds. The 
fact that the maternal cares are by this species imposed upon others, and that the mother herself hastens 
to the mountains during the most heated time of the summer, suggests the probability of the Cowbird 
belonging to some ultra fashionable circle of society. However this may be, it is certain* that the species 
has attained an unenviable notoriety among its associates as well as among ornithologists. 
Cowbirds during their residence in the state may frequently be seen in flocks of a dozen to fifty or 
more, following the cows or cattle as they graze. They sometimes alight upon the animals, and sit con- 
tentedly for considerable time if undisturbed. Their fondness for cows and cattle is one of the many 
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