FAMILY TIIRAUPIDAE 



445 



upper surface yellow-ocher (darker, more orangish in costaricensis) , 

 darkest on upper tail coverts; wing coverts as upper back; remiges and 

 rectrices drab dark brown; throat dingy buff; band across breast 

 greenish orange (passerinii) or dark orange (costaricensis) ; rest of 

 undersurface yellow-ocher (more greenish in passerinii, more brownish 

 in costaricensis) . 



At least some immature males appear to change into adult plumage 

 in an irregular manner, as individuals with scattered black feathers in 

 the plainer immature dress, and others with varying mixtures in the 

 extent of the black, are frequent. In occasional birds the red of the adult 

 plumage is modified to orange, and orange or reddish hues may appear 

 as a wash or a definite pattern over parts of the body. Early workers, 

 with limited material were misled by the more striking aberrations, and 

 described several as distinct species. 



The Scarlet-rumped Tanager is common in gardens and second 

 growth in the lowlands of Bocas del Toro and Chiriqui and the Pacific 

 slope of Veraguas. Nominate passerinii is found on the Caribbean 

 slope from Panama north to southeastern Mexico. R. p. costaricensis is 

 confined to the Pacific slope of western Panama and Costa Rica. This 

 tanager inhabits the vegetation that grows up after forest has been 

 cleared; in the Chiriqui highlands, it is regularly found to 1200 m in 

 suitable habitat, and I have seen it as high as 1560 m in low growth 

 bordering recently cleared land near El Volcan. It feeds on a variety 

 of fruits and insects, for which it will glean foliage, forage on the 

 ground, or flycatch. Frequently it forms groups: Moriarty (Wilson 

 Bull., 1977, p. 152) observed 34 flocks in Costa Rica, of which 5 were 

 mixed with other species; he found that in larger flocks this tanager has 

 an increased foraging rate, an increased group movement, and usually 

 feeds higher in the tree canopy than when in smaller groups. Skutch 

 (Pac. Coast Avif., no. 31, 1954, pp. 123-165) found groups of at least 

 a dozen roosting together. 



The Scarlet-rumped Tanager has a variety of call notes, including a 

 nasal ac or wac, a dry pzzt, and a sharp whip. A scolding note is 

 slightly higher in sound than that of R. dimidiatus, but, aside from this 

 very minor difference, is the same in the 2 species. Skutch found that 

 R. p. costaricensis is a more frequent and forceful singer than the nomi- 

 nate race; the song is an endlessly repeated, somewhat robinlike, sim- 

 ple phrase of three or four notes. 



The Gorgas Memorial Laboratory banding station at Almirante, 

 Bocas del Toro, has recovered many Scarlet-rumped Tanagers banded 

 there in earlier years. The lengthiest recovery of which Dr. Pedro 



