ART. 10 BIRDS OF PINCHOT EXPEDITION FISHER AND WETMORE 37 



BUTEO GALAPAGOENSIS (Gould) 



Galapagos hawk 



Polyborus galapagoensis Gould, Proc. Zool. Soc. London, October 3, 1837, 

 p. 9. (Galapagos Islands.) 



This interesting hawk, the only species of its family known to 

 inhabit the Galapagos group, was seen on all the larger islands 

 visited except Tower Island, where very likely it simply escaped 

 notice. In size and in other respects it suggests our broad-winged 

 hawk. Its nests were found on Seymour, Indefatigable, and Hood 

 Islands, and at this season were empty except for an addled egg 

 found on Seymour. The nests were placed on lava outcrops and on 

 account of their size and elevation could be seen at a considerable 

 distance. (PI. 7.) They were at least 3^/2 feet in diameter and 

 about the same in height, much like a well-formed haycock but 

 not so rounded on top. The mass was made up of tree branches, bits 

 of weed stalks, and other rubbish, with finer material on top, bearing 

 a shallow depression. As the birds were seen on and in the vicinity 

 of the nests at frequent intervals, it is likely that the breeding season 

 was approaching. 



Polyandry, at least among North American birds of prey, seems 

 to be unknown. It was of great interest, therefore, to find a female 

 of the Galapagos hawk receiving sexual advances from two males. 

 A female and two males were seen quite frequently about a nest on 

 Seymour Island or flying in sight of one another in search of food. 

 On June 20 all three birds were present in the vicinity of the nest, 

 the female sitting on one of the larger trees, 35 to 40 yards distant. 

 AVhile the observer was quietly stationed near the nest, one of the 

 males flew and alighted on the limb close to the female. Almost 

 immediately they began their courtship and sexual union soon was 

 accomplished. The male then flew and alighted near the observer, 

 while almost immediately his place at the side of the female was 

 taken by the second male. Very soon his mating advances were 

 received as had been those of his predecessor and their connubial 

 relations were completed. There was no indication of jealousy on 

 the part of either male, and the birds departed at different times but 

 flew in the same general direction. 



These hawks were very tame and showed no fear when approached 

 within a few feet. They were photographed in both still and mov- 

 ing pictures, and the operator stood not over a yard away. Once to 

 induce a hawk to leave a tree and go to its nest to be photographed, 

 it was necessary to climb the tree and push the hawk off the limb 

 by placing the muzzle of a gun against its underparts. On Hood 

 Island, Doctor Mathewson fed lizards to a hawk by presenting 

 them attached to a short stick. "When the hawk had difficulty in 

 detaching the preferred morsel with its beak it used its foot sue- 



