A Field Study of the Wrenthrush, Zeledonia coronata

IN describing the monotypic genus Zeledonia Robert Ridgway (1888) wrote, "This remarkable new genus is so peculiar in its characters that I am in much doubt as to which family it belongs." For over 80 years systematists have shared Ridgway's uncertainty. Pycraft (1905), who published the only analysis of the Wrenthrush's anatomy, asserted, "there can be no doubt about the Turdine affinities of Zeledonia." He also established that Zeledonia' has only 9' obvious primaries and 10 rectrices. These conflicting statements prompted Ridgway (1907: 885) to erect the monotypic family Zeledoniidae. Since that time Zeledonia has been grouped either with the Turdidae (Mayr and Amadon, 1951; Ripley, 1952, 1964; Beecher, 1953) or in the family Zeledoniidae (Hellmayr, 1934; Eisenmann, 1955; Wetmore, 1960). Sibley (1968) presented new evidence from egg-white protein analysis showing that placement of Zeledonia in or near the Turdidae is incorrect. His findings indicate that Zeledonia is a true nine-primaried oscine, and Sibley (1970) has placed the genus in a monotypic tribe Zeledoniini, beside the tribe Parulini, in his family Fringillidae. The present paper presents evidence from a life history study that supports placement of Zeledonia among the nine-primaried oscines. The Wrenthrush is found only in Costa Rica and western Panama. Slud (1964) cites records from the Cordillera de Tilarfin, the Cordillera Central, the mountains bordering the southern edge of the central plateau, and the Cordillera de Talamanca. Hellmayr (1934) notes specimens from Volcfin de Chiriqui in western Panama. Slud (1964) describes the distribution in Costa Rica as follows: "Vertically it ranges in the cloud-forested highlands from a low of about 4000 feet in some places, 5000-60.00 feet in others, to timber line. It is quite common, particularly in the portions that are almost constantly drenched." The morphological characters of Zeledonia, particularly the rounded