RED-EYED COWBIRD. 



Callothrus robustus Ridgway. 



IJg^HE Red-eyed Cowbird, or Bronzed Cowbird is an inhabitant of the lower Rio 

 Grande region of Texas, south through Mexico and Central America to Panama. 

 It has been found as far north as San Antonio, Texas. 



Like the common Cowbird the female deposits her eggs in the nests of other birds, 

 and the beautiful Orioles of that region, Audubon's Oriole, the Hooded Oriole, the 

 Orchard Oriole, and Bullock's Oriole, appear to be the especial victims, and among these, 

 according to Major Charles Bendire, Audubon's seems to be the worst sufferer. In nine 

 sets of this species in the United States National Museum Collection there are only two, 

 w^hich contain the normal number of eggs, four. The other seven all contain from one 

 to three of these parasitic eggs, with one or two of their own, and some of these are 

 usually punctured. In none of these nests were eggs of the Dwarf Cowbird found in 

 addition to those of the Bronzed Cowbird. The former appears to confine itself to the 

 smaller Orioles only. 



We are indebted to Dr. J. C. Merrill, U. S. Army, for the following account of this 

 parasite : 



"My first specimens were taken at Hidalgo, on the Rio Grande, seventy miles 

 north-west of Fort Brown, where, however, they are not so abundant as lower down 

 the river. Here they are common throughout the year, a small proportion going south 

 in winter. Those that remain gather in large flocks with the Long-tailed Grackles, 

 common Cowbirds, and Brewer's, Red-winged, and Yellow-headed Blackbirds; they 

 become very tame, and the abundance of food about the picket lines attracts them for 

 miles around. The Red-eyed Cowbird is readily distinguishable in these mixed gatherings 

 from the other species by its blood-red iris and its peculiar top-heavy appearance, caused 

 by its habit of pufiing out the feathers of the head and neck. 



"This habit is most marked during the breeding season and in the male, but is 

 seen throughout the year. 



."About the middle of April the common Cowbird, Brewer's, and Yellow-headed 

 Blackbirds leave for the North ; the Long-tailed Grackles have formed their colonies in 

 favorite clumps of mesquite trees ; the Redwings that remain to breed have selected sites 

 for their nests ; the Dwarf Cowbirds arrive from the South, and the Red-eyed Cowbirds 

 gather in flocks by themselves and wait for their victims to build. The males have now 

 a variety of notes, somewhat resembling those of the common Cowbird, but more harsh. 

 During the day they scatter over the surrounding country in little companies of one or 

 two females and half a dozen males, returning at nightfall to the vicinity of the picket 

 lines. While the females are feeding or resting in the shade of a bush, the males are 

 eagerly paying their addresses by puffing out their feathers, as above noted, strutting 

 up and down, and nodding and bowing in a very odd manner. Every now and then 

 one of the males rises in the air, and poising himself two or three feet above the female, 

 flutters for a minute or two, following her if she moves away, and then descends to 



