234 BIRDS OF THE REPUBLIC OF PANAMA — PART 2 



species, seen regularly over Panama City and the Pacific side of the 

 Canal Zone, are of this race, but proof of this awaits the taking of 

 specimens. 



In 1944 I found these swifts common on Isla San Jose, but had 

 some difficulty in collecting the first specimens as the birds spent most 

 of their time circling above the forest that covered the island, where 

 they were beyond gun range. In February and March frequently they 

 were associated in pairs which often sailed close together with wings 

 set at an angle above the back. From a dozen to 50 fed together, 

 circling above the trees with rapidly beating wings. Rarely I heard 

 them utter high-pitched chattering calls. Later, when engineers had 

 cut broad roadways through the forest the swifts frequently came 

 lower over these openings, so that from the middle of February to 

 early September Dr. J. P. E. Morrison, my companion who remained 

 on the island after my departure, secured a long series for specimens. 

 Immature birds taken July 6 have the rump and upper tail coverts 

 grayer, less brownish. Some specimens taken June 27 and July 4 

 showed molt in the wing coverts, and in 1, primaries were under re- 

 newal September 10. 



Three taken on Isla Coiba January 10 and 15, 1956, are typical 

 of this race, as are 3 secured on Isla Canal de Afuera, between Coiba 

 and the mainland, on March 21, 1962. These individuals, all females, 

 were near breeding stage. Other swifts of this species were recorded 

 but not collected on adjacent Isla Afuerita March 22, and others were 

 seen on Isla Brincanco in the Contreras group, March 24, and at 

 Caleta Cayman, on the western end of Isla Cebaco, March 28. On 

 Isla Coiba, from the regularity with which small groups circled around 

 the line of coconut palms back of the beach after the sun had set, I 

 had the impression that they sought sleeping quarters in these trees. 



Small swifts have been rare on the eastern side of the Azuero 

 Peninsula. My only sight records were at Paris, Herrera, March 4, 

 1948, and at Tonosi, Los Santos, March 25, 1957. 



CHAETURA CINEREIVENTRIS PHAEOPYGOS Hellmayr: 

 Gray-rumped Swift, Vencejo de Rabadilla Gris 



Chactura cinereiventris phaeopygos Hellmayr, Bull. Brit. Orn. Club, vol. 16, 

 May 8, 1906, p. 83. (Carillo, Costa Rica.) 



A small swift, black above with gray rump and upper tail coverts. 



Description. — Length 105 to 114 mm. Adult (sexes alike), above 

 dull black, including wings and tail ; rump and upper tail coverts ash 

 gray, the feathers when in fresh plumage very narrowly tipped with 



