THE BIRDS OF ISLA COIBA, PANAMA 
By ALEXANDER WETMORE 
Research Associate, Smithsonian Institution 
(WitTH 4 PLATEs) 
INTRODUCTION 
Isla Coiba, largest island on the Pacific coast of Central America, 
lies well at sea to the west of the lower end of the Azuero Peninsula, 
at lat. 7°20’ to 7°40’ N. and long. 81°36’ to 81°54’ W. The island 
trends northwestward and southeastward, with a length of 214 miles 
and a greatest width of 13 miles. It is well watered, with numerous 
small streams running down from the rough, broken interior, where 
two separated high points near the center rise to about 1,400 feet 
above the sea. A lower hill, about 1,150 feet high, stands in the 
center of the northern end, while the southern end is mainly lower 
ground. The island bulges to the westward, while on the eastern side 
there is the large indentation of Bahia Damas, and the smaller one 
of Ensenada Arenosa. A broad valley, now mainly cleared to form 
cultivated fields and pastures, lies back of the large bay mentioned. 
It is drained by the parallel streams of the Rio San Juan and Rio 
Catival, which are actually a single river system, separated in their 
lower ends only by swampy land. 
The entire island is covered with heavy virgin forest, except along 
the lower courses of the larger streams where there are swampy 
woodlands, succeeded to seaward by stands of mangroves. In the 
San Juan area these are of considerable extent. Rocky headlands 
project along the coast, with sand beaches, some of considerable ex- 
tent, between them, broken by mangroves at the river mouths. The 
land rises back of the shore rather steeply to elevations of 80 to 250 
feet, and then slopes back to the interior ridges, which in many 
places are steep-sided and much broken. 
Near the projecting point on the western side of Boca Grande, at 
the extreme southern end of Bahia Damas I noted many fragments 
of coarse-grained sandstone, wave-worn into flattened, lenticular 
form, piled up on the beach. Elsewhere the numerous exposures 
along the eastern shore of Coiba and on Isla Rancheria are an altered 
SMITHSONIAN MISCELLANEOUS COLLECTIONS, VOL. 134, NO. 9 
