I40 BIRDS OF THE REPUBLIC OF PANAMA PART 3 



by narrow channels. In a thorough survey in February and March 

 1944 of the large Isla San Jose, distant at the southwest from others 

 in the group, it was not present. Nor did I find it in 1960 in visits 

 to islas Contadora, Saboga, Chapera, Santelmo, and Bayoneta. 



The characters that mark these birds of the islands are slight, but 

 are such that the population is evidently different from that of main- 

 land Panama. As these are birds of weak flight, it may be supposed 

 that they reached the Pearl Islands at low sea level after the close of 

 Pleistocene time when these lands were part of the mainland. 



THAMNOPHILUS BRIDGESI Sclater: Bridges' Ant-shrike, Pavita 

 Hormiguera de Bridges 



Thamnophilus bridgesi P. L. Sclater, Proc. Zool. Soc. London, pt. 24, August 



15, 1856, p. 141. (David, Chiriqui, Panama.) 

 Thamnophiltis puncfatus Cabanis, Journ. f. Orn., vol. 9, July 1861, p. 241. (Costa 



Rica.) 



Small ; in form like the Barred Ant-shrike, but male black, with 

 scattered white dots on the wing coverts ; female head black, breast 

 gray, both streaked with white. 



Description. — Length 150-165 mm. Adult male, upper surface, 

 including the tail, head, foreneck, upper breast, and under tail coverts 

 deep black ; most of wing coverts tipped with small white spots ; four 

 outermost rectrices in fresh state with a small white spot at tip, part 

 or all lost as the feathers wear ; lower breast, abdomen, and sides slate 

 color; inner webs of under side of rectrices, and under wing coverts 

 white, the inner under coverts spotted lightly with slate ; upper back 

 with a concealed median white spot on each feather. 



Adult female, crown, hindneck, sides of head and of neck black, 

 streaked narrowly with white ; back and scapulars slaty brown, be- 

 coming paler on the rump and upper tail coverts ; wings and tail 

 brownish black ; wing coverts black, spotted with white ; chin and 

 throat white, edged broadly with black to produce prominent streaks ; 

 rest of under surface gray to olive-gray lined with white, heavily 

 on breast, partly concealed and less evident on abdomen ; under tail 

 coverts spotted and barred faintly with white ; inner borders of 

 wing feathers, under wing coverts and axillars white ; upper back 

 with a concealed white line near the middle of each feather. 



Immature male, black of forepart of body duller with foreneck and 

 breast streaked narrowly with white. 



Immature female, breast, sides, and abdomen duller, browner. 



Juvenile, dull grayish brown on upper surface and wings, the 



