FAMILY FORMICARIIDAE I35 



THAMNOPHILUS DOLIATUS PACIFICUS Ridgway 



Thamnophilus doliatus pacificus Ridgway, Proc. Biol. Soc. Washington, vol. 21, 

 October 20, 1908, p. 193. (Chinandega, Nicaragua.) 



Characters. — Male, with the crown feathers extensively whiter ; 

 black bars on under surface slightly wider, so that the under surface 

 appears somewhat darker. Female, averaging slightly darker above 

 and below. 



In a male taken near Puerto Armuelles, Chiriqui, March 9, 1966, 

 the iris was yellowish white ; cutting edge of maxilla and all of 

 mandible bluish neutral gray ; rest of maxilla black ; tarsus, toes, and 

 claws rather dull neutral gray. 



Measurements. — Males (10 from Chiriqui, Costa Rica, Nicaragua, 

 and El Salvador), wing 67.6-71.7 (69.9), tail 52.7-59.3 (56.2), 

 culmen from base 20.8-23.4 (21.5), tarsus 25.8-28.8 (27.3, average 

 of 9) mm. 



Females (10 from Chiriqui, Costa Rica, and Guatemala), wing 

 66.1-69.5 (67.8), tail 51.3-59.5 (55.8), culmen from base 19.3-21.9 

 (20.7), tarsus 25.6-27.5 (26.7) mm. 



Resident. Locally, tolerably common in the Tropical Zone of 

 western Chiriqui from the Costa Rican boundary eastward, inter- 

 grading with T. d. nigricristatus in the valley of the Rio San Felix, 

 above San Felix. Found in small number in the mangrove swamps 

 on the coast northeast of Puerto Armuelles, more common inland 

 to the north above Concepcion, Alanje, and near David. 



From published records these birds appear less numerous now 

 than 70 to 100 years ago. Early collectors reported them common 

 near Divala, Bugaba, and David. In my own studies there in 1960 

 I found them in fair number only on the coastal area below Alanje, 

 mainly near the Rio Chico and westward. Elsewhere, clearing for 

 pastures and farms has destroyed the thickets that are their normal 

 haunt. To the westward in this area there were a few in the borders 

 of the mangrove swamps near the mouth of the Rio Palo Blanco. 

 Inland and to the south down the Burica Peninsula where the darker 

 ant-shrike, Thamnophilus bridgesi, was common, I did not encounter 

 them. If any are present they must be rare and local. To the north 

 and west T. d. pacificus ranges from southern El Salvador and 

 western Honduras through western Nicaragua and western Costa 

 Rica. 



While this subspecies, in the extensive white in the crown of the 

 head in the male and in its average darker coloration, is readily 

 separated from the race nigricristatus of eastern Panama, it should 



