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, 
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 
