NORTH AMERICAN BIRDS. 207 



The eggs are deposited at intervals of two to five days, and fre- 

 quently young are found in the nest with partially incubated eggs. 

 Two to four are usually laid. Dr. Howard Jones, in " Nests and Eggs 

 of the Birds of Ohio," says that when incubation does not begin until 

 the complement is completed, as is commonly the case, four eggs, 

 rarely six, make up the set. Mr. Norris has a set of six. The average 

 size of twenty-eight specimens is 1.27 x .89. Fresh eggs may be found 

 as early as the middle of May, in June, July and even August. Not 

 infrequently are the eggs of the Yellow-billed and Black-billed Cuckoos 

 found in the same nest. The color of the eggs is glaucous-green, of 

 the same tint found in heron's eggs, which fades upon exposure to 

 light, and when incubated, this color becomes several shades lighter 

 than that in the fresh specimens. 



* * Coccyzus americanus occidentalis Ridgw. 



California Cuckoo. 



Hab. Western United States, north to Oregon, east to New Mexico and Colorado, south over table- 

 lands of Mexico. 



Prof. Ridgway describes this western form as larger than C. amer- 

 icanus^ with proportionately larger and stouter bill.* Mr. Norris has 

 a set of three eggs taken with the parent bird June 4, 1888, near Salem, 

 Oregon. The nest was the usual platform of sticks, which is charac- 

 teristic of this family ; situated in a cottonwood tree, on an island in a 

 river. The eggs are of a bright pea green, and measure i.iix.83, 

 1.07 X .83, I.I2X .84. Incubation had commenced, and the eggs in this 

 case more nearly approach those of C. erythrophthalmus in color than 

 those of C. ainericamts. 



388. Coccyzus erythrophtlialnius (Wils.) [388.] 



Black-billed Cuckoo. 



Hab. Eastern North America, north to Labrador and Manitoba, westward to the Rocky Mountains 

 south in winter to the West Indies and Tropical America. 



The same names are given to this bird as are common to the 

 Yellow-billed Cuckoo, C. americanus^ and their general habits are 

 similar. The nests of the Yellow and Black-billed Cuckoos resemble 

 each other closely, and it is not always possible to diflferentiate 

 the two. Nests of the former are often found which could not 

 be mistaken for those of the Black-billed on account of the coarse- 

 ness of the nest, larger .size and paler color of the eggs. How- 

 ever, as a rule, the nest of the Black-bill is constructed with more 

 care, the sticks being somewhat smaller, the catkins less numerous, and 

 the whole woven together in a firmer manner. The eggs are smaller, 

 less elliptical, and are of a darker green — deep glaucous-green or verd- 



'^'For description see Manual of North American Birds: p. 273. 



