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BIRDS OF THE REPUBLIC OF PANAMA PART 4 



guas eastward, and found in smaller numbers in the foothills up to 900 

 m, particularly in Darien, where it has been collected at Cerro Tacar- 

 cuna and Cana; it inhabits forest, borders, and shrubby areas. I have 

 seen this oriole in a wide range of habitats, from high forest in Darien 

 to dense thorn scrub behind the beach at Nueva Gorgona, Panama. 

 This race is found also in northern Colombia and northern Venezuela; 

 other forms occur north to southeastern Mexico, although it is absent 

 in Costa Rica. Although Panamanian birds and those from parts of Co- 

 lombia have been referred by some authors to the race hondae (e.g., 

 Meyer de Schauensee, Caldasia, vol. 5, 1951, pp. 873-1112; Blake, 

 Check-list Birds World, vol. 14, 1968, p. 151), Olson (Proc. Biol. Soc. 

 Wash., vol. 94, no. 2, 1981, pp. 363-373) has shown that this name can 

 so far be applied only to the 2 type specimens from Honda, in the upper 

 Magdalena Valley of Colombia. 



I have observed the Yellow-backed Oriole in pairs and groups of up 

 to 6 or 8 that may represent family units, since during March and April 

 I have seen adults accompanied by birds still in immature plumage that 

 were probably born the preceding year. Leek (Auk, 1974, p. 163) has 

 seen this species feeding on the nectar of balsa tree (0 * chroma limon- 

 ensis) flowers and E. A. Goldman's notes from Cana mention it being 

 especially common where Hcliconia is abundant. The stomachs of 2 

 birds he collected there contained the following: 9 caterpillars 64%, 

 elytra of a cistelid 1%, roach remains 20%, arachnid remains 10%, 17 

 seeds not determined 5%; 2 cerambycids 15%, 4 ants 20%, 2 weevils 

 (Cryptorhynchini) 15%, an ichneumon fly 20%, 5 orthopteran jaws 

 10%, caterpillar skin 5%, arachnid remains 10%, bits of mollusk shell 

 5%. Two males collected by Strauch (Bull. Brit. Orn. Club, 1977, p. 

 64) weighed 50.1 and 57.7 g. 



This oriole sings persistently throughout the day. The song is a 

 series of 4 to 8 clear whistles going up and down the scale in a manner 

 that sounds labored, but is nonetheless musical. When excited, they 

 call whink-whink-whink rapidly. Ridgely (1976, p. 311) notes "a teea, 

 cheep-cheep, cheep (the cheep's nasal); also has a part-chatter, part 

 buzzy whistle kzwee-kzwee-kzwee-kzwee-kzwee and a nasal nyeh-nyeh- 

 nyeh-nyeh." Eisenmann (in litt.) has also noted a clear, whistled song 

 of four to six notes, pee, pu, pua-pu, pey, with variations, which sounds 

 like a tune whistled off key. 



As with /. mesomelas, I never collected an individual of this species 

 that was in breeding condition during my visits to Panama from De- 

 cember to April. Eisenmann and Willis (Smiths. Cont. Zool. 291, 



