624 REPORT OF NATIONAL MUSEUM, 1893, 



Their extreme sociability affects tlieir breeding habits, for sometimes 

 the flock does not break up in spring, and several females lay in one 

 nest together; but whether the birds are paired or practice a pro- 

 miscuous intercourse, I have not been able to discover. They have a 

 great partiality for the large domed nests made by the Aiiiimhins 

 acHiicaudatus, called Leilatero in the vernacular. One summer a flock 

 of about 10 Bay-wings took i^ossession of a LenaUro's nest on one of 

 my trees, and after a few cays I took 14 eggs from it. Though the 

 birds hopped, chirping around me, numifesting great solicitude, the 

 eggs were quite cold, and had I left them many more would have been 

 laid no doubt; but as they were piled up 3 or 4 deep in the nest they 

 could never have been hatched. 



As a rule, however, the flock breaks up into pairs, and then a neat, 

 well made nest is built in the fork of a branch, lined with horsehair; 

 or, oftener still, a Lertater<>\s nest is seized, the Bay-wings fighting with 

 great spirit to get i)OSsession, and in it, or on it, their own nest is made. 

 Like their relations, the common Cowbird, they seem strongly attracted 

 by domed nests, and yet shrink from laying in the dark interior. As a 

 rule, when they have captured a Le)latrro\s nest they break a hole in 

 the side and so admit the light and form an easy entrance One sum- 

 mer a pair of Bay-wings attacked a Le)lafeyo\s nest on one of my trees, 

 the fighting was kept up for three or four days, and then at the foot of 

 the tree I found .") young LenaUros, fully fledged, which had been 

 pecked to death and thiown out of the nest. 



The eggs of the Bay-wing are 5 in number, nearly round, and densely 

 marked with dusky reddish brown. 



Once I observed 2 young Bay wings following a Yellow-breast, 

 Fseudoleistes riresceiis, with their usual peculiar hungry cry, and while 

 I watched them they were fed several times by their foster parents 

 Naturally I concluded that the Bay-winged Cowbird is sometimes para 

 sitical on other species, but I never saw anything afterward ^o comfirm 

 nie in that belief, and I believe now that I was mistaken, and that the 

 young Bay-wings were not real Bay-wings, but the young of MolutJirus 

 ru/oaxUlaris. 



