28o SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I50 



camis americamis, while smaller, varies from 325 to 360 mm. regard- 

 less of location in the vast region that it inhabits. Occasional in- 

 dividuals in this population range slightly larger to 363 mm. though 

 these larger specimens are uncommon. 



FALCO PEREGRINUS ANATUM Bonaparte: Peregrine Falcon; Halcon 



Peregrino 



Falco Anatum Bonaparte, Geogr. and Comp. List, 1838, p. 4. (Egg Harbor, New 

 Jersey.) 



A large hawk (largest of the falcons found in Panama), with long 

 pointed wings ; a broad black stripe on the side of the head below and 

 behind the eye. 



Description. — Length, male 390 to 430 mm., female 440 to 500 mm. 

 Adult, head, including cheeks, and hindneck black, the crown washed 

 with gray; back, wing coverts, and secondaries, light gray, with 

 faint, irregular crossbars of darker gray and fuscous, and shaft lines 

 of black ; primaries black, washed lightly with gray, with a white 

 line around tip ; under surface white to buffy white, with throat, fore- 

 neck, and upper breast immaculate, or with a few dark lines; else- 

 where, including tibia and under wing, barred narrowly with fuscous- 

 black ; under side of primaries barred with dark gray and white. 



Immature, brownish black above, with the feathers edged very 

 narowly with brownish white ; tail with indistinct broken crossbars of 

 dull buffy white ; primaries black ; side of head and throat white, with 

 a bold band of black on the cheeks ; underneath white to buff, streaked 

 heavily with dull brown to fuscous-black; under wing buffy white, 

 with irregular blotches and cross bars of fuscous; under surface of 

 primaries dark gray, with narrow bands of dull buffy white. 



The tarsus is short and the foot large, the middle toe being as long 

 as the tarsus. 



Measurements (from Friedmann, U.S. Nat. Mus. Bull. 50, pt. 11, 

 1950, p. 652).— Males, wing 301-327 (314.2), tail 138-154 (145.1), 

 culmen from cere 18-21 (19.6), tarsus 46-54 (50.6) mm. 



Females, wing 340-376 (356.3), tail 167-192 (178.9), culmen from 

 cere 20-25 (23.4), tarsus 50-57 (54.4) mm. 



Migrant and winter visitor from the north. Fairly common ; mainly 

 in the lowlands; Isla Coiba; Isla Taboga; Archipielago de las Perlas 

 (San Jose, Contadora). 



Peregrines arrive in October (Oct. 14 earliest date), and remain 

 through April, occasionally later (May 3, Changuinola; May 5, Barro 

 Colorado Island). 



