l6o SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I50 



their feet they may seize small bits of such refuse and pull it back 

 away from the water. About large carcasses dozens congregate with 

 much scrambling, jostling, and fighting, in which the black vultures by 

 force of number often crowd out the turkey vultures. Only when 

 the king vulture, the cacicon, arrives do they fall back. The rapidity 

 with which a band of black vultures will strip a dead horse or cow 

 to bare bones and shreds of hide is remarkable. Often when a feeding 

 group is disturbed one or two scramble out of the body cavity where 

 they have been concealed amid the ribs. 



At abattoirs groups of black vultures gather as animals are killed. 

 On such occasions they run and hop about in much excitement while 

 forced to wait, often holding the tail partly erect over the back, an 

 odd attitude that gives them the appearance in outline of huge rails. 

 It is then that the hissing sigh that is their usual note is most often 

 heard. Though ordinarily aggressive when a number are together I 

 have seen a laughing gull refuse to give way to a single vulture that 

 attempted to seize a bit of fish on which the gull was feeding. 



Animal carrion is the main sustenance of the black vulture, but on 

 occasion it takes vegetable food. At Almirante they fed on ripe 

 avocados in trees growing beside the houses, and when the fruits 

 tumbled to the ground descended to finish them there. I have seen 

 them eating scraps of the soft meat of coconuts (pipas) that had 

 been drained of fluid and cast aside. And they also eat the oily pulp 

 covering the seeds of some of the palms. 



In the Canal Zone dozens gather in evening to roost in the trees on 

 the slopes of Ancon Hill, and many soar for hours here in the strong 

 air currents, particularly during the dry season. Elsewhere I have 

 observed scattered individuals or small groups coming to roost in 

 coconut and other tall palms. At La Jagua one season two slept on a 

 dead stub, where they were exposed to the strong sweep of the wind. 

 At Panama Vie jo in evening many come out from the city to roost in 

 palms and other trees. 



While silent in the main, I have heard them utter a low, guttural 

 note, croo-00-00 croo croo, varied to a husky aspiration, hwuh-h-h, 

 repeated several times. 



The eggs, normally 2 in number, are laid in a hollow log, a hole 

 in a tree base, under matted vegetation in low rastrojo, or, in hill coun- 

 try, in cavities among rocks. There is no nest lining. On Isla Coiba 

 in 1956 convicts working in the fields reported that the vultures had 

 begun to nest the middle of January. On March 20, 1961, at La 

 Jagua I found two half -grown young in a dense stand of spiny pita 

 at the border of forest beside the marsh. They ran out when poked 



