SCREAMING COW-BIRD 105 



April 15. This morning I started in quest of 

 the Bay-wings, and observed one individual, that 

 had somehow escaped detection the day before, 

 assuming the purple dress. This bird I shot ; and 

 after the flock had re-settled a short distance off, I 

 crept close up to them, under the shelter of a hedge, 

 to observe them more narrowly. One of the adults 

 was closely attended by three young birds ; and 

 these all, while I watched them, fluttered their wings 

 and clamoured for food every time the old bird 

 stirred on its perch. The three young birds seemed 

 precisely alike ; but presently I noticed that one of 

 them had a few minute purple spots, and on shooting 

 this one I found it to be a young M. rufoaxillaris t 

 while the other two were true young Bay- wings. 



The hunger-cry of the young M. badius (Bay- 

 wing) is quite different from that of the young M. 

 bonariensis : the cry of the latter is a long, shrill, 

 two-syllabled note, the last syllable being prolonged 

 into a continuous squeal when the foster-parent 

 approaches with food ; the cry of the young M. 

 badius is short, reedy, tremulous, and uninflected. 

 The resemblance of the young M. rufoaxillaris to 

 its foster-brothers in language and plumage is the 

 more remarkable when we reflect that the adult bird 

 in its habits, gestures, guttural notes, also in its deep 

 purple plumage, comes much nearer to M. bonariensis 

 than to M. badius. It seems impossible for mimicry 

 to go further than this. A slight difference in size 

 is quite imperceptible when the birds are flying 

 about ; while in language and plumage the keenest 



