332 BIRDS OF THE REPUBLIC OF PANAMA PART 4 



white or buffy white marked with brown spots. They measured 21.9 X 

 17.3 and 21.2x16.9 mm. 



This nest was abandoned, but another found May 21 was identical 

 in appearance and situation. It contained 2 young birds probably not 

 more than 3 days old. They were sparsely covered with down and their 

 eyes were still shut. Their mouth linings were orange. The young of 

 this nest died a few days later, but a third nest found June 26 had 2 

 nestlings about 10 days old. By 15 days these young were fully 

 feathered; 2 days later, when Hunt had to leave the area, the nestling 

 he had not collected was still in the nest, indicating a longer pre-fledging 

 period than that of any other wood warbler. 



Family ICTERIDAE: Blackbirds and Orioles, Turpiales y Chacareros 



The Icteridae are an exclusively American family that has its great- 

 est diversity in the tropics. Twenty-two species have been found in 

 Panama, including 5 migrants from temperate North America. The 

 icterids are medium- to large-sized birds, mostly boldly patterned in 

 black with yellow, red, or orange, or entirely black. The oropendolas 

 are the largest passerines in the tropics; along with the caciques and the 

 Giant Cowbird, they have the ability to produce loud noises with their 

 wings when in flight that are sometimes part of courtship displays. An- 

 other peculiarity of many of the larger icterids is a strong musky odor. 



The icterids are particularly interesting for the diversity of their 

 breeding behavior. The oropendolas and some of the caciques live in 

 colonies in isolated or exposed trees, where females outnumber males 

 and weave long, pendulous nests. Other caciques and the orioles nest 

 in solitary pairs, while the Red-breasted Blackbird and Eastern Mea- 

 dowlark sometimes form loose colonies in large fields and savannas. 

 The Panama cowbirds are parasites with varying degrees of special- 

 izations, from the Shiny and Bronzed Cowbirds, which put their eggs 

 in the nest of a variety of small birds, to the Giant Cowbird, which 

 parasitizes only the colonial oropendolas and caciques. 



All the icterids have powerful voices, some of which are loud and 

 raucous, while others produce very fine songs. Their diet is varied, in- 

 cluding insects, fruit, seeds, and nectar. The Great-tailed Grackle regu- 

 larly scavenges and takes small vertebrate prey including nestling birds; 

 there are records of oropendolas snatching birds as well. 



Although the Dickcissel, Spiza americana, is usually included with 

 one or another of the finchlike groups, Raikow's (Bull. Carnegie 

 Mus. Nat. Hist., vol. 7, 1978, pp. 1-43) examination of the limb myol- 



