FAMILY SYLVIIDAE 



177 



visible from above or the sides. Kiff (in litt.) describes it as "a large 

 compact open cup composed mostly of green moss interspersed with a 

 few slender stems and fern fronds. It was lined with fine rootlets and 

 plant stems. The outer diameter of the nest was 22 X 16 cm, and it was 

 about 12 cm in depth. The inner cup was 3 cm in diameter and 2 cm 

 deep." Two other nests of Phainoptila from Costa Rica were dis- 

 covered in similar situations at the same time of year. 



The 2 eggs from Kiff's nest were "subelliptical in shape and slightly 

 glossy. They had a grayish-white ground color with a dense sprinkling 

 of fine light gray, purplish brown and dark brown spots over their en- 

 tire surfaces. Each egg contained a slightly developed embryo." They 

 measured 27.84x20.30 and 27.19x19.20 mm, with empty dry shell 

 weights of 0.274 and 0.260 g, respectively. Kiff concludes that, "aside 

 from their somewhat blunter shape," the eggs of Phainoptila melano- 

 xantha "are simply larger versions of those of Phainopepla nitens or 

 Ptilogonys cinereus" 



Family SYLVIIDAE: Gnatwrens and Gnatcatchers, Cazajejenes 



The gnatwrens and gnatcatchers are both usually placed in the family 

 Sylviidae, the Old World warblers. Some put the gnatcatchers in a sub- 

 family (Polioptilinae) of a broadened Muscicapidae, which also in- 

 cludes the subfamily Sylviinae, or in an entirely separate family, the 

 Polioptilidae, or reduce them to a tribe ( Polioptilini) of the Sylviinae. 

 The gnatwrens have in the past been considered to be wrens or even 

 antbirds; Rand and Traylor (Auk, 1953, p. 334-337) and Parkes 

 (Proc. Biol. Soc. Wash., vol. 93, 1980, pp. 61-67) review the history of 

 their classification. Although gnatwrens superficially resemble ant- 

 birds, they have an oscine syrinx. Rand and Traylor concluded that 

 Ramphocaenus and Microbates are most closely allied to certain Old 

 World warblers, especially the African genus Macros phenus, than to 

 Polioptila, Beecher (Auk, 1953, pp. 279, 328) considers resemblances 

 to Old W 7 orld genera to be convergent. 



Of the 9 species of gnatcatchers, 2 are found in Panama. They share 

 the typical gnatcatcher characters of a slim build, gray and white plum- 

 age, and a long tail continually wagged or cocked as the bird flits 

 through the foliage searching for insects. The gnatwrens are also in- 

 sect eaters and, like the gnatcatchers, build cup-shaped nests that often 

 are decorated with mosses, leaves, or lichens. 



