Parasitic Birds 321 



two female birds were using the nest. Subsequently he 

 found that this was the case, but it turned out that they 

 were of different species, and that the Bay-winged Cow- 

 bird (M. badius) was actually parasitic on one of its own 

 relations, leaving the task of bringing up its family to 

 M. rufoaxillaris. 



Nor is the above the only instance in which birds of the 

 same genus are parasitic on one another, for Dr. E. A. Goeldi, 

 the Director of the Museum at Para, states that one of the 

 Hang-nests (Cassidix oryzivorus] places its egg in the nest 

 of another Hang-nest (Cassidix persicus}. Further south, 

 in the neighbourhood of Rio de Janeiro, it victimizes other 

 Hang-nests of about its own size, such as Ostinops decuma- 

 nus, and probably Cassicus hamorrhous. 



A very curious nesting habit has been developed in the 

 Black Cuckoo of Central and South America, called " Ani," 

 in some places known as the " Savana Blackbird" (p. 295). 

 Of Crotophaga ani in Jamaica, Mr. W. E. D. Scott writes as 

 follows 



" Their nesting habits are exceedingly curious and 

 interesting. Many individuals (possibly members of one 

 flock) work together in the construction of a large nest, in 

 which all the females of the company lay their eggs. 

 The number of eggs deposited in different nests varies 

 greatly, but it is of course dependent on the number of 

 birds in a company. Six and eight eggs are commonly 

 found. I once took eleven, and in August last year I saw 

 a clutch of twenty-one that had been taken from a single 

 nest ! It is probable that normally not more than two 

 eggs are deposited by each bird, but nothing definite can be 

 said on this point. The nest, which is usually placed high 

 up in a tall tree, very frequently in a clump of mistletoe on 

 a bastard cedar, is a large loosely-constructed mass of 

 twigs, entirely lined with dry leaves. But the most re- 

 markable circumstance in connection with the nesting of 



Y 



