346 



BIRDS OF THE REPUBLIC OF PANAMA PART 4 



I found at Chilar, Colon, on March 7, 1952, had 15 or 20 nests in a tree 

 over the Rio Indio. Their baglike nests give the oropendolas the local 

 name of chacarero, because the nest suggests the chacara, a knit bag 

 used by the country people. Salvadori and Festa (Bol. Mus. Zool. 

 Anat. Comp. R. Univ. Torino, vol. 14, no. 339, 1899, p. 5) noted that a 

 native name in Darien was uropendulo. 



The nesting season in Panama seems to begin later than that of other 

 oropendolas. On March 9, 1951, 1 shot 2 females at La Campana, Pan- 

 ama, that had ovaries beginning to develop. On March 22, 1949, I saw 

 females looking at nesting sites at Chico, Panama. I saw females carry- 

 ing food to young in the nest on April 22, 1949, at Chepo, Panama. 

 In March 1981, Ridgely (in lift.) found nests under construction in 

 Cana, Darien. In the Canal Zone the nesting season extends into late 

 June (Ridgely, in litt.). Courtship and nest construction by the race 

 P. d. insularis on Trinidad are discussed in great detail by Drury (Zoo- 

 logica, 47, pt. 1, 1962, pp. 39-58). A photograph in Nature (vol. 219, 

 1968, p. 690) shows a light-colored egg with a few dark marks. Schafer 

 (Bonner. Zool. Beitr., 1951, pp. 1-148) writes that in Venezuela eggs 

 were white, pale gray, or pink with dots and spots of black irregularly 

 scattered over the larger end. Two eggs measured 23x34 mm and 

 each weighed 12 g. The clutch was 1 or 2. 



When preparing specimens of this oropendola I noted that the oil 

 gland was very large and contained considerable thickened fluid which 

 I did not encounter in any other oropendola. Two females collected by 

 Strauch (Bull. Brit. Orn. Club, 1977, p. 64) weighed 178.3 and 191.8 g. 



In July 1975, Ridgely (in litt.) found a roost at Matuganti (above 

 the mouth of the Rio Pucro) that contained 2000-2500 oropendolas 

 and caciques. Of these, probably over 1000 were Crested Oropendolas, 

 with Yellow-rumped Caciques, Black and Chestnut-headed Oropen- 

 dolas, and Giant Cowbirds in diminishing proportions. 



CACICUS CELA VITELLINUS (Lawrence): Yellow-rumped Cacique, 

 Charro de Rabadilla Amarilla 



Cacicus vitellinus Lawrence, 1864, Proc. Acad. Nat. Sci. Philadelphia, p. 107. 

 ("New Greneda, Isthmus of Panama.") 



Rather large; all black except for bright yellow lower back, rump, 

 undertail coverts, and small patch on wing coverts; bill pale yellow. 



Description. — Length, male 268-292 mm, female 223-233 mm. Adult 

 male, body all black except for lower back to upper tail coverts, lower 

 abdomen, and undertail coverts, which are rich yellow to orange-yellow; 



