28 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I50 



particularly on the hindneck ; grayer, less brown, on f oreneck, upper 

 breast, and sides of head. 



Measurements. — Males (13 specimens), wing 130.0-138.0 (132.1), 

 exposed culmen 23.6-26.1 (24.3, average of 12), tarsus 41.3-47.2 

 (44.7), middle toe with claw 57.1-64.1 (60.7, average of 6) mm. 



Females (8 specimens), wing 119.2-131.0 (123.6), exposed culmen 

 20.6-23.1 (21.9), tarsus 39.4-42.0 (41.5), middle toe with claw 53.3- 

 59.0 (56.4, average of 2) mm. 



Resident. Fairly common locally in the Canal Zone on the back 

 waters of Gatun Lake, and on the Rio Chagres above Gamboa; 

 grebes seen on Madden Lake probably are of this race. Breeds 

 rarely in the marshes of the Rio La Jagua, eastern Province of 

 Panama, where I collected a fully grown immature bird on June 

 27, 1953. There is also an immature in first fall plumage in the 

 Museum of Comparative Zoology labeled Tocumen taken July 25, 

 1936. 



The first report of the race for the isthmus is that of Van Tyne 

 (Auk, 1937, p. 379) who shot an adult male in breeding condition 

 at Barro Colorado Island in Gatun Lake on August 5, 1927. I have 

 taken several on the Rio Chagres between Gamboa and Juan Mina, 

 where these birds are fairly common. 



There are no records as yet in Panama east of La Jagua. It 

 remains to be learned whether birds that breed at the Cienaga 

 Macana, near El Rincon, Herrera (that I saw here in March 1948), 

 belong to the present subspecies or to the preceding one. 



On January 13, 1961, a pair had pulled together a mass of aquatic 

 plants to serve as the base of a nest opposite the dock at Juan Mina, 

 A few days later this had been destroyed and the birds had moved, 

 disturbed by my traveling in and out in cayucos. By January 18, 

 other mated pairs were scattered through the bays and side channels 

 bordering the main river, but I saw no other nests. 



PODICEPS DOMINICUS BRACHYPTERUS (Chapman): Least Grebe; Tigua 



Figure 6 



Colymbus dominicus brachypterus Chapman, Bull. Amer. Mus. Nat. Hist., vol. 

 12, Dec. 23, 1899, p. 256. (Lomita Ranch, Hidalgo County, Texas.) 



Size and general form of a small duck, but with long, slender neck, 

 thin, pointed bill, and feet placed far back on the body; in flight 

 with definite white markings at the ends of the secondaries. 



Description. — Length 200 to 230 mm. Adult (sexes alike), dusky 

 gray above, whitish below, with light-colored eyes. 



