440 LIFE HISTORIES OF NORTH AMERICAN BIRDS. 



It is ludicrous to see a fat, fully fledged young Cowbird following a pair of 

 Chipping Sparrows, or some small Warbler, clamoring incessantly for food, and 

 uttering its begging call of " seerr-seerr" most persistently, only keeping quiet 

 while its gaping beak is filled with some suitable morsel, and stra»ger still to note 

 how devoted the diminutive nurses are to their foster child. One would think 

 that they might see through the fraud, at least after the young interloper leaves 

 the nest, if not before, and abandon him to his fate; but the greatest attachment 

 seems to exist between them until the Cowbird is able to shift for himself, when 

 he leaves and joins his oSvn kind. 



It has been asserted that Cowbirds occasionally build nests and rear their 

 own young in the West, but this is undoubtedly incorrect, and on projjer 

 investigation it will probably be found that the supposed Cowbird is really 

 Brewer's Blackbird. 



When the laying season is over they collect again in larger flocks and 

 frequent the marshes, in company with the Blackbirds, where at that time of the 

 year they find an abundance of food, and the return migration to tlieir winter 

 homes begins usually in the latter half of October. 



The shell of the Cowbird's egg is compact, granulated, moderately glossy, 

 and relatively nuich stronger than that of its near allies, the Icferidce. The ground 

 color varies from an almost pure white to grayish white, and less often to pale 

 bluish or milky white, and the entii-e surface is tisually covered with specks and 

 blotches varying in color from chocolate to claret brown, tawny, and cinnamon 

 rufous. In an occasional specimen the markings are confluent and the ground 

 color is almost entirely hidden by them; in the majority, however, it is distinctly 

 visible. These markings are usually heaviest about the larger end of the egg, 

 and in rare instances they form an irregular wreath. The eggii vary greatly 

 in shape, ranging from ovate to short, rounded, and elongate ovate, the first 

 predominating. 



The average measurement of one hundred and twenty-seven specimens in 

 the United States National Museum collection is 21.45 by 16.4-2 millimetres, or 

 0.84 by 0.60 inch; the largest egg measures 25.40 by 16.76 millimetres, or 1 

 by 0.66 inch; the smallest, 18.03 by 15.49 millimetres, or 0.71 by 0.61 inch. 



The t}'pe specimen. No. 20157 (PI. 6, Fig. 3), represents one of the lighter- 

 marked types, and was taken by the writer near St. Louis, Missouri, on June 24, 

 1873, from a nest of the Yellow-breasted Chat; this contained three other eggs, 

 one of Avhich was deposited by the Cowbird and two by the other species. 

 No. 20160 (PI. 6, Fig. 4), also from the Bendire collection, represents one of 

 the more finely spotted eggs of this species. It was taken from a nest of the 

 Mountain Song Sparrow, in El Paso County, Colorado, on Jidy 2, 1874; this 

 also contained another Cowbird's egg and three eggs of the rightful owner. 

 Both of these are large specimens. No. 25463 (PI. 6, Fig. 5) represents an 

 average-sized and a heavily marked specimen in which the ground color is pretty 

 well hidden, and was taken by Dr. A. K. Fisher, near Sing Sing, New York, 

 from a nest of the Red-eved Vireo, containing two eggs of its own in addition 

 to that of the parasite, on June 6, 1880; and No. 25721 (PI. 6, Fig. 6), in the 



