8 28 The Sparrow-like Birds 



weeks the Cow-bird was full grown and had left his foster parents to join the 

 increasing flocks of his kind. It is not an uncommon sight to see a Warbler 

 or small Sparrow feeding a young Cow-bird larger than itself, and Mr. Hudson 

 speaks of seeing the young Argentine Cow-bird being fed by the Reed Tyrant, 

 a little Flycatcher hardly half the size of the Cow-bird. The little thing flew 

 directly to its large foster offspring, and, alighting on its back, dropped a worm 

 into the upturned mouth, a performance he saw repeated many times. 



Argentine Cow -birds. Of the three species of Cow-bird found in Argentina, 

 Mr. Hudson has given us a very full and interesting account. The Bay-winged 

 Cow-bird (M. badius) builds a nest for itself, or expels the owners of some other 

 nest, adapting it to its own use, and lays usually five eggs, which are incubated 

 and the young reared in the proper manner. It is apparently never parasitic 

 itself, but, curiously enough, it is the species usually selected as foster parent 

 by the Screaming Cow-bird (M . rufoaxillaris), whose eggs so exactly resemble 

 those of the Bay-wing as to be indistinguishable. The young for some time are 

 so similar to those of the Bay-wing that they cannot be distinguished, and it is 

 not until they assume the full first plumage that the species can be differen- 

 tiated. The completeness of this adaptation is perhaps without a parallel in 

 nature. The remaining species the Argentine Cow-bird (M. bonariensis] 

 is perfectly parasitic, selecting a number of small birds, but never, apparently, 

 its near relative the Bay-wing. In the eggs of this species there is the most 

 extraordinary diversity in color, form, and disposition of the markings, hardly 

 any two, even those laid by the same bird, being alike. For example, they 

 range in color from pure white to a fine deep red, and the degree of spotting 

 and marking is almost infinite. This may or may not be an adaptation for plac- 

 ing their eggs in nests where they will most closely resemble the eggs of the 

 owners, but it certainly suggests this hypothesis. 



The American Orioles, or Hang-nests, whose generic designation (Icterus} 

 gives name to the family, form a very large group of more than fifty species 

 and subspecies. They are found over the whole of temperate and tropical 

 America, reaching their greatest development within the tropics, and are usually 

 richly colored birds, with sharply contrasted areas of black and orange, black 

 and yellow, or black and chestnut. The females and young are mostly plainer 

 with much of greenish olive. Of the six or eight forms visiting the United 

 States, the Baltimore Oriole (/. galbula) is by far the best known and most prized, 

 its coming being eagerly watched for, and fortunate indeed does the house- 

 holder consider himself when the "Golden Robin," or "Hang-nest," decides to 

 build his wonderful swinging cradle in the elm tree overhanging the home. 

 The male has the head, neck, throat, and upper back black, and the breast, 

 abdomen, lower back, and lesser wing-coverts a deep rich orange or orange- 

 yellow, sometimes becoming intense orange or almost flame-scarlet. The wings 

 are black as are the middle pair of tail-feathers, the others being light orange 

 or orange-yellow. The Baltimore Oriole usually arrives at its summer home 

 early in May, the males generally preceding the females by two or three days. 

 They frequent the open country along shade -bordered roads, creek bottoms, 



