CUCULID.E—CUCULIN.E: TREE CUCKOOS. 



609 



and breeds throughout about half of its N. Am. range in June and July, sometimes in May and 

 August. I have found it nesting in Assiniboia near the Dakotan border. Nest preferably in 

 bushes and small trees, often quite near the ground, rarely on it, a frail flat structure of twigs 

 with miscellaneous softer materials for lining ; eggs I.IO X 0.80, pale bluish or greenish, usually 



Via. 420. — Black-billo<l Cuckoo. 



deeper-colored, less elliptical and averaging smaller than those of the Yello\v-l)illed Cuckoo, 

 though probably not to be distinguished with certainty. They vary in lengtli from O.f't' to 

 1.18, and in breadtli from 0.75 to 0.90; tlie number found in nest is usually 3, 4, or 5, but e.v- 

 coptionally 2 to 7, almost invariably in difl'crent stages of incubation; they are occasionally 

 dropped in the nest of the yellow-billed species, but only e.vceptionally slipped in nests of other 

 birds, as a Dove's, Robin's, Catbird's, Flycatcher's, Warbler's, or Sparmw's. Kircs variously 

 atlvanced in iiicubatiou are ordinarily found in the saiiic ii<>t witli tli'duliiiL'-^ of difTiTcnt aires. 



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