78 



BIRDS OF THE REPUBLIC OF PANAMA PART 4 



THRYOTHORUS RUFALBUS CASTANONOTUS (Ridgway): 

 Rufous-and-white Wren, Cucarachero Rojizo 



Thryophilus rufalbus castanonotus Ridgway, Proc. Boston Soc. Nat. Hist., vol. 

 XXIII, March, 1888, p. 386. ("Nicaragua to the highlands of Columbia" = 

 Angostura, Cartago, Venezuela.) 



Medium size: above chestnut-brown, a prominent white line above 

 the eye; undersurface white, except for brownish flanks. 



Description. — Length 135-155 mm. Adult (sexes alike), upper sur- 

 face pale to deep chestnut (lighter on crown); wings narrowly, tail 

 more broadly, barred with black; a distinct white superciliary line, 

 margined narrowly above by black; line on side of head from the eye 

 to neck rufous-brown; rest of side of head white, streaked with black, 

 with lower side of head white, bordered below by a narrow black line; 

 undersurface white, changing to grayish brown on sides, browner, be- 

 coming darker on flanks; underwing coverts spotted with black; under- 

 tail coverts white, barred heavily with black, the dark bars edged nar- 

 rowly with rusty brown. 



Immature, duller, darker brown above, especially on crown and hind- 

 neck; duller white on lower surface, with breast lined distinctly with 

 dusky; undertail coverts pale rusty brown, barred lightly with black. 



An adult male, collected at Chiva Chiva, Canal Zone, March 19, 1961, 

 had the iris dark brown; cutting edge of maxilla and mandible dull 

 whitish; rest of maxilla fuscous-black; base of gonys and anterior half 

 of mandible (except cutting edge) pale neutral gray; tarsus, toes, and 

 claws brownish gray. Another male at Las Palmitas, Los Santos, Janu- 

 ary 24, 1962, had the iris dark reddish brown; maxilla and tip of mandi- 

 ble black; rest of mandible light neutral gray; tarsus, toes, and claws 

 light mouse brown. 



Measurements. — Males (10 from Chiriqui, Veraguas, Los Santos, 

 Herrera, Code, Province of Panama, and Canal Zone), wing 67.2- 

 72-1 (69. 3), tail 48.2-54.7 (52.1), culmen from base 19.7-23.6 (21.3), 

 tarsus 24.2-25.7 (25.0) mm. 



Females (10 from the same localities as the males), wing 61.2-67.8 

 (64.3), tail 46.2-51.5 (48.4), culmen from base 19.5-21.5 (19.7), tarsus 

 23.8-25.0 (24.5) mm. 



Resident. Widely distributed on the Pacific slope in the lowlands, 

 where it is locally common in thickets and deciduous woodland, from 

 western Chiriqui to the Rio Bayano Valley, following clearings into the 

 highlands, and on the Caribbean side of the Canal Zone (especially mid- 

 dle Chagres Basin and adjacent Colon Province, but rather rare near 



