THE CUCKOO 471 



tcnaeit). Tin- cuckoo threw her head hack, opened her jreat orange- 

 colourod mouth, and squawked loudly in protest, thus making clear 

 that she was not carrying her egg in her beak. Possibly she carried it, 

 like the ("rows, in the pouch under the tongue. She placed it in the 

 robin's nest in spite of their resistance, which appeared to cease 

 during the act of deposition itself. 1 This was also the wise with a 

 pair of shrikes. When the cuckoo was at the nest they remained to 

 all appearance quite indifferent, though previously they had shown 

 every sign of resentment* 



The question of the origin of this strange parasitism of the cuckoo 

 is one of extreme difficulty, to which it is impossible to do justice 

 within the limits of the present chapter. The answer, if ever reached, 

 can be the result only of a careful comparative study of the various 

 degrees of this form of parasitism as manifested not only in the 

 behaviour of different species of cuckoo, but of species belonging to 

 quite different families and orders, such, for example, as the cow- 

 hirds (Molvbrux), which belong to the Pasaeres. 



A few examples of the variations in parasitism must here suffice. 

 The yellowbilled-cuckoo (Coccyzus americanw) usually builds a nest 

 and incubates its eggs. The nest is a frail platform, off* which 

 the eggs easily roll. It is itself liable to fall owing to its slight- 

 ness, which is said to be the reason why this cuckoo occasionally 

 lays its eggs in the nests of other species, including that of the black- 

 billed-cuckoo. The latter returns the compliment, and is still more 

 decidedly parasitic in its habits. 3 One of the American cowbirds 

 (M. bonaritntu) occasionally attempts to build nests, but leaves them 

 unfinished, and drops its eggs into the nests of other species, often 

 laying several in the same nest 4 Another cowbird (M. ater) appears 

 to be M parasitic as our cuckoo. It puts its eggs in the nests of other 

 species, sometimes in old, deserted, or unfinished nests ; sometimes, 

 again, if pressed, on the ground. From one to seven cowbird's eggs 



1 Zoologist, 1000, 2024 (A. H. Meiklejohn). * Journal fUr Ornithologi*, 1858, 100. 



' Charles Bendire, Life-Ilitorieuof N. American Bird*, 1886, 10. 

 4 W. H. Hudson. Argentine Ornithology- 



