JAN., 1909. BIRDS OF ILLINOIS AND WISCONSIN CORY. 



161 



Family CUCULID^. Cuckoos. 



Feet, zygodactyle (two toes in front, two behind) ; first primary, 

 about half as long as third ; outer tail feathers, much shorter than 

 middle ones. 



Yellow-billed Cuckoo. 



Upper parts, brownish gray, with faint gloss of greenish; under 

 mandible, mostly yellow ; greater portion of primaries, rufous brown, 

 tipped with grayish olive; under parts, dull white; outer tail feathers, 

 black, tipped with white. Coccyzus americanus. 



Yellow-billed cuckoo. 

 See No. 185. 



Upper parts, grayish brown, with faint gloss of green; bill, black; 

 no rufous brown on primaries; under parts, dull white; outer tail 

 feathers, like back in color. Coccyzus erythrophthalmus . 



Black-billed Cuckoo. 

 See No. 186. 



