FAMILY PODICIPEDIDAE 27 



PODILYMBUS PODICEPS PODICEPS (Linnaeus) 



Colymbus podiceps Linnaeus, Syst. Nat., ed. 10, vol. 1, 1758, p. 136. (South 



Carolina). 



Characters. — Adult, browner on the foreneck and on the sides 

 of the head, and faintly lighter, on the average, on the dorsal surface ; 

 juvenile, until nearly grown retains streaks on head and neck, with 

 the background color of this area darker. 



Measurements. — Males (13 specimens), wing 124.6-134.3 (129.6), 

 exposed culmen 20.8-23.7 (22.7), tarsus 40.0-43.8 (42.3), middle 

 toe with claw 55.3-57.0 (56.2, average of 7) mm. 



Females (18 specimens), wing 115.0-125.7 (120.4), exposed cul- 

 men 17.3-20.8 (19.3), tarsus 35.5-41.0 (38.5), middle toe with claw 

 47.7-54.0 (51.7, average of 14) mm. 



Resident. Breeding locally in Bocas del Toro. Migrant elsewhere 

 in western Panama during the period of northern winter. 



Mated birds were seen in February 1958 on one of the temporary 

 water impoundments at Changuinola ; and on March 141 shot a laying 

 female there. Eisenmann (Condor, 1957, p. 249) saw adults and 

 young in juvenile plumage in the same area at the end of June 

 1956. A skin of this subspecies recorded by Peters (Bull. Mus. 

 Comp. Zool., vol. 71, 1931, p. 302) as a bird of the year, taken 

 December 22, 1927, near Almirante, may have been from the 

 resident stock or a northern migrant. It is probable that this race 

 is the one that nests around the lakes near El Volcan in Chiriqui, 

 where I noted males calHng in March 1954; and on February 19, 

 1960, I saw one, apparently an adult male, that appeared to be 

 guarding a nesting territory. Some of those seen there seemed to be 

 northern migrants, as in 1954 I noted a decrease in their number at 

 the end of the first week in March. 



Two immature birds in the British Museum (Natural History) 

 collected by Enrique Arce in Veraguas, one of them, taken in 1869, 

 marked "Castillo," also are of this race. It is probable that migrants 

 will be found east as far as the Gatun and Madden lake areas. 



PODILYMBUS PODICEPS ANTARCTICUS (Lesson) 



Podiceps antarcticus Lesson, Rev. Zool., vol, S, July 1842, p. 209. (Valparaiso, 

 Chile.) 



Characters. — The race antarcticus differs from typical Podilymbus 

 p. podiceps in longer and heavier bill and in larger foot; wing on 

 the average longer; adult somewhat darker on the dorsal surface. 



