U. S. NATIONAL MUSEUM BULLETIN 211 



One cowbird's egg in a nest is evidently the prevailing rule, but two 

 eggs, often laid by two different females, are not a rare occurrence 

 and we have numerous records of three or more in a nest. A. C. 

 Reneau tells me that he has twice found three eggs in the nest of a 

 phoebe and once in the nest of a Bell's vireo. A. D. Du Bois' list 

 contains a record of three eggs in a cardinal's nest, three in a wood 

 thrush's nest and five in another nest of a wood thrush. Frank R. 

 Smith writes to me of three eggs in the nest of a wood thrush, de- 

 posited before the thrush had laid any eggs, and apparently laid by 

 different females. T. S. Roberts (1932) says: "Three or four are 

 uncommon, though Mr. Kilgore and the writer once found a Wood 

 Thrush's nest containing two eggs of the Thrush and six of the Cow- 

 bird, the latter of two distinct patterns, suggesting that two Cowbirds 

 had laid three eggs each in this nest. * * * At Mille Lacs on July 7, 

 1934, Mr. Marius Morse found a Willow Thrush's nest containing 

 two eggs of the owner and eight of the Cowbird. * * * Apparently 

 four different Cowbirds had laid one or more eggs each." 



J. H. Langille (1884) writes: "I have frequently found more than 

 one in the same nest; once not less than four in the nest of a Scarlet 

 Tanager, which had only room enough left for two of her own. Mr. 

 Trippe once found a Black-and-white Creeper's nest with five of the 

 eggs of the interloper and three deposited by the owner." Isaac E. 

 Hess (1910) mentions a scarlet tanager covering four eggs of the 

 cowbird and an oven-bird's nest that contained seven eggs of the 

 parasite. I have already mentioned the case of a catbird sitting on 

 four cowbird's eggs and one of her own. F. A. E. Starr writes to me : 

 "I once found a red-eyed vireo's nest with the vireo sitting on six 

 cowbirds' eggs and none of her own. A nest of the Wilson thrush was 

 found containing one egg of the thrush and four eggs of the cowbird." 

 Sanborn and Goelitz (1915) report a towhee's nest that "contained one 

 Towhee egg and eight Cowbird eggs." 



Bendire (1895) describes the eggs as follows: 



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

 relatively much stronger than that of its near allies, the Icteridae. The ground 

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

 bluish or milky white, and the entire surface is usually 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 eggs vary greatly in 

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

 dominating. 



