FAMILY PARULIDAE 



279 



March, when it is found on sides of breast also; underwing coverts 

 white. 



Female and immatures, as male, but crown and back usually remain- 

 ing olive-yellow; side of face remaining gray, and chestnut only on 

 sides, often absent entirely. 



Measurements. — Males (10 from Panama), wing 61.2-66.5 (64.2), 

 tail 45.7-50.6 (48.3), oilmen from base 10.7-11.9 (11.2), tarsus 16.0- 

 18.6 (17.3) mm. 



Females (10 from Panama), wing 56.1-61.0 (59.2), tail 43.6-48.8 

 (46.0), culmen from base 10.5-11.3 (10.9), tarsus 15.8-18.0 (17.0) 

 mm. 



Winter visitor from the north. Very common in the lowlands and 

 less common in the highlands of Chiriqui; reported as common east 

 through the mountains of Veraguas (Santa Fe, Chitra), ranging east 

 through the Canal Zone to western San Bias (Mandinga) and eastern 

 Province of Panama (Chico, Chepo). In the lowlands it is found 

 widely, from Puerto Armuelles and Divala, Chiriqui; Paracote, south- 

 ern Veraguas; Almirante, Bocas del Toro; and El Uracillo, on the 

 Caribbean slope of Code; to the Canal Zone. It is not reported to date 

 from the eastern side of the Azuero Peninsula. I noted 2 on Isla Coiba 

 January 12 and 29, 1956, and Ridgely (in litt.) saw 1 there on April 13, 

 1976. E. A. Goldman wrote in his notes that in 1911 this was the "most 

 abundant North American warbler in the northern half of the Canal 

 Zone from January 12 until April 18 when the last specimen obtained 

 was taken at Gatun." It decreases considerably after March. In 

 Darien there are "few" records (Griscom, Bull. Mus. Comp. Zool., vol. 

 78, 1935, p. 368). 



The earliest record for Panama is September 7 (Willis and Eisen- 

 mann, Smiths. Contrib. Zool., no. 291, 1979, p. 26); Ridgely (in litt.) 

 has found individuals as late as April 25 (1980, Changuinola, Bocas 

 del Toro) and May 1 (1976, Ft. Sherman, Canal Zone). Evidently 

 many individuals remain in the same locality for several months — of 

 those banded by Loftin et al. (Bird-Banding, 1966, p. 41) at Curundu, 

 in the Canal Zone, 1 banded December 8, 1963, was taken at the same 

 locality February 9, 1964. Another banded at Curundu December 3, 

 1963, was recaptured there April 2, 1966 (Loftin et al., Bird-Banding, 

 1967, p. 151). 



The Chestnut-sided Warbler is found most often in second-growth 

 woodland, clearings, and edges, often in groups with other migrant 

 warblers. 



