SEVEN NEW WHITE-WINGED DOVES 



17 



and not the breeding subspecies of the Nayarit mainland. In dis- 

 cussing the disparity in male bill lengths between some of the main- 

 land and the island birds, Grant correctly diagnosed the reason for 

 this difference when he inferred that it might be due to the presence 

 of migrants in the mainland sample. 



The nearest breeding population on the mainland is near San Bias, 

 Nayarit, mostly in or near the mangrove swamps. The 22 adult males 

 I examined from this part of the mainland were breeders I collected 

 mostly in that locality and near Escuinapa, Sinaloa, in April 1960. 

 Their bills average almost 2 mm. shorter than those of mearnsi. In 

 late autumn, winter, and early spring, the population of mearnsi in 

 drier woodlands and fields of this coastal plain and foothills of these 

 States, many of them from Arizona as proved by band recoveries, 

 greatly outnumbers that of palustris, which is much more local in 

 distribution. 



A series of 25 specimens from the Mexican mainland of Sinaloa 

 and Nayarit nearest the Tres Marias includes no individuals that 

 have the principal characteristics of insularis. The latter are distinctly 

 different although these islands are only 65 miles offshore, west of San 

 Bias, Nayarit. 



SPECIMENS EXAMINED 



Mexico: Nayarit: Tres Marias Islands, Maria Madre. 



Field studies in Guatemala in 1942, 1946, and 1947 provided 

 many observations on the biology of white-winged doves there. A 

 series of specimens from the dry woodlands was first recorded as 

 mearnsi (Saunders et al., 1950) . Later study showed that these repre- 

 sented a new race whose principal range is in the dry woodland of 

 the Pacific piedmont hills of Central America. This new race may be 

 called: 



Zenaida asiatica collina^ new subspecies 

 Piedmont White-winged Dove 



CHARACTERS 



Compared with alticola, collina is paler and smaller and has shorter 

 wings and tail. It has shorter wings and tail than monticola. It is 

 slightly larger than australis, averages paler on the underparts, and 

 lacks the cinnamon brown tone to the breast and upperparts which 

 usually characterizes that race. Also, it is grayer on the back and 

 rump, and usually more purple on the crown than australis. Com- 

 pared with panamensis, collina has longer wings and averages darker 

 on the breast and upperparts. Compared with asiatica, collina is 

 slightly larger, and its wings and tail are longer. Compared with 



