528 BIRDS OF THE REPUBLIC OF PANAMA PART 3 



of mandible, except at tip, pale brownish white ; rest of bill black ; 

 tarsus and basal phalanges of anterior toes, the hindtoe, and all claws, 

 neutral gray ; rest of anterior toes pale neutral gray. 



A female at Chiman, Panama. February 16, 1950, had the iris 

 ivory-yellow ; gonys brownish yellow ; rest of bill brownish black ; 

 tarsus and toes grayish brown. Another female, at Juan Mina, Canal 

 Zone, January 16, 1961, had the iris Marguerite yellow; base of 

 mandibular rami, line along their lower margin, and also along gonys, 

 dull white ; rest of bill dark neutral gray ; tarsus, toes, and claws 

 neutral gray. A third of this sex, collected at Pucro, Darien, Janu- 

 ary 30, 1964, had the iris pale orange ; cutting edge of maxilla and 

 mandible, base of gonys, and lower margin of mandibular rami pale 

 dull ivory-white ; rest of bill black ; tarsus dark neutral gray ; toes 

 brownish neutral gray ; claws dull fuscous. 



The tarsus and toes in olivaceum, in the long series of specimens 

 available from the eastern half of the Isthmus and northern Colombia, 

 are uniformly dark. Those of O. cinereigulare are light, faintly 

 brownish yellow. 



Measurements. — Males (10 from Canal Zone, eastern Province 

 of Panama, western Colon, northern slope of Code, and San Bias), 

 wing 46.6-48.8 (47.4), tail 33.2-36.7 (34.7) culmen from base 

 12.1-13.3 (12.7), tarsus 15.0-15.9 (15.3) mm. 



Females (10 from western Colon, Canal Zone, eastern Province 

 of Panama, Darien, and San Bias), wing 41.0-43.8 (42.5), tail 28.6- 

 31.8 (30.3), culmen from base 11.6-12.8 (12.3), tarsus 13.9-15.1 

 (14.4) mm. 



Resident. Locally common in the tropical lowlands, on the Pacific 

 slope from the southern Canal Zone east through Darien ; on the 

 Caribbean side from the Rio Indio in western Colon and northern 

 Code, east through the Canal Zone, eastern Colon, and San Bias to 

 Colombia ; to Cana on Cerro Pirre. 



These small birds live in the under story of forest areas, and range 

 out also into low second growth through fields and pastures. Occa- 

 sionally I have found them in tall, dense stands of grasses bordering 

 thickets. Usually they are timid, so that their presence is known 

 only from their calls, uttered by birds that remain hidden among the 

 leaves. Rarely, I have found them on perches occasionally fairly 

 high above the ground, in open branches in tall forest, when in move- 

 ment they may suggest small vireos. It is usual to see one alone. 

 Rarely, where two have been in company, I have found that they were 

 male and female. Rarely also, I have noted one in company with 



