57o 



BIRDS OF THE REPUBLIC OF PANAMA PART 4 



Measurements. — Males (10 from Darien), wing 50.8-55.0 (53.6), 

 tail 41.9-46.4 (44.4), culmen from base 10.0-10.9 (10.2), tarsus 13.8- 

 15.5 (14.7) mm. 



Female (8 from Darien and San Bias), wing 51.0-54.0 (52.1), tail 

 40.2-45.5 (43.2), culmen from base 10.0-10.9 (10.4), tarsus 14.6-15.8 

 (15.1) mm. 



Resident. Common on both slopes east of the Canal Zone and on 

 the Pacific slope in Code, Los Santos, and Veraguas. Birds in western 

 Veraguas (Sona) and on Isla Gobernadora appear to be intergrades 

 with hoffmanni. Of 2 birds collected on Gobernadora one was typical 

 of hicksii and the other was more similar to specimens of hoffmanni 

 from Isla Coiba. Beyond Panama, hicksii extends south along the Pa- 

 cific slope of Colombia to the vicinity of the Rio Dagua, Valle. 



SPOROPHILA AMERICANA "AURITA" (Bonaparte) 



Spermophila aurita Bonaparte, 1850, Consp. Gen. Av., 1(2), p. 497. ("Bras.[il]" 

 — PPanama.) 



Spermophila semicollaris Lawrence, 1863, Ann. Lyc. Nat. Hist. N.Y., 8, p. 10. 



(Lion Hill, Panama Railroad.) 

 Spermophila fortipes Lawrence, 1865, Ann. Lyc. Nat. Hist. N.Y., 8, p. 172. (Line 



of Panama Railroad.) 



Characters. — Extremely variable, ranging from individuals similar 

 to hicksii, but with slightly more black in the rump, throat, or belly, to 

 individuals nearly as black as corvina. 



A male taken at the Peluca Hydrographic Station, Colon, February 

 23, 1961, had the iris dark brown; bill black; tarsus fuscous; claws 

 black. 



Measurements. — Males (10 from the Canal Zone), wing 51.0-56.6 

 (54.3), tail 41.3-50.5 (46.3), culmen from base 10.3-12.3 (11.4), tar- 

 sus 14.5-18.0 (16.3) mm. 



Females (10 from the Canal Zone), wing 52.0-54.6 (53.0), tail 42.6- 

 45.5 (45.2), culmen from base 10.7-11.8 (11.2), tarsus 14.5-17.0 

 (15.6) mm. 



Olson (Proc. Biol. Soc. Wash., vol. 94, 1981, p. 380-390) has ap- 

 plied the name "aurita" to the birds from the hybrid zone created by 

 intergradation of hicksii and corvina in the area of the Canal Zone. No 

 pure parental types occur in this zone. By the use of a hybrid index, 

 Olson determined that about 63% of these intergrades were intermedi- 

 ate between the two parental types, whereas 18% were closer to corvina 

 and 20% were more like hicksii. Specimens assigned to "aurita" are 



