8 CUCKOOS AND SHRIKES IN" RELATION TO AGRICULTURE. 



to four. The European cuckoo, like our cowbird, lays its eggs in the 

 nests of other birds ; a reprehensible habit not shared by its American 

 cousin, although occasional instances of such parasitism have been 

 observed. Our cuckoos do not ostensibly rear more than one brood in 

 a season, but they frequently lay their eggs at intervals, so that the 

 young hatch successively, the later eggs being incubated in part by the 

 young. 



Three species and two subspecies occur in the United States. Of 

 these, one vspecies and one subspecies are restricted almost entirely to 

 the southern coast of Florida, and are properly West Indian birds. 

 The others occupy practically the whole country, except the plains and 

 deserts, though in winter they are found in the extreme southern part 

 only. The j^ellow-billed cuckoo {Goccyzus americanus) breeds from the 

 Gulf of Mexico to southern Canada; the black-billed {Goccyzus eryth- 

 rophthalmus) ranges still larther north. The northward migration does 

 not begin until spring is weW advanced, and is usually completed by 

 the end of May. Most of tlie birds leave the Northern States in 

 August, but some linger through September and even into October. 



From an economic standpoint cuckoos rank among our most useful 

 birds. Their habit of remaining concealed in foliage suggests, and • 

 close observation i)roves, tbat their diet consists for the most part of 

 insects — very largely caterpillars — found on trees and shrubs. 



EXAMINATION OF STOMACHS. 



In the laboratory of the Biological Survey 109 stomachs of the yellow- 

 billed and 4:(i of tlie blai-k-billed cuckoo were examined. All were taken 

 between INIay and October, inclusive, except one of the yellow-billed 

 collected in Texas in January. These stomachs were obtained in 

 twenty States, the District of Columbia, and Canada, and were fairly 

 distributed over the country from Louisiana and Texas to Canada, and 

 from Massachusetts to Kansas and Nebraska. A greater number would 

 have been desirable, but tlie contents of those examined were so uni- 

 form that it seems fair to infer that they give a reasonably accurate 

 idea of the general food of the species. It has been deemed best to 

 treat the two species together, smve they prove to be very much alike 

 in diet. The greatest ditlerence is that the yellow-billed cuckoo eats 

 more beetles (Coleoptera) and fewer bugs (Hemiptera). The seasonal 

 variation in diet is much less than in most birds. Of the 155 stomachs 

 of both s])ecies examined, only one contained any vegetable food, 

 and this only two berries of the wild rough-leaved cornel {(Jornus 

 asperifolia). One other stomach contained a bit of rubbish, probably 

 taken accidentally with som<! insect. Drs. C. Hart Merriam and A. K. 

 Fisher have seen the yellow-billed species feeding on mulberries in 

 Westchester County, N. Y.,' and Dr. B. H. Warren found 'berries' in 



Annuiil Rei)()rt, U. S. l)('i)t. Af^riciiltmo for 18!tn, p. 285, 



