^^3 FIELDIANA . ZOOLOGY Published by CHICAGO NATURAL HISTORY MUSEUM Volume 44 May 28, 1962 No. 11 Birds of the Sierra Macarena, Eastern Colombia Emmet R. Blake Curator, Division of Birds The Sierra Macarena is an isolated chain of forest-covered moun-tains about seventy-five miles long, rising from the low plains, or llanos, of southwestern Meta to a maximum altitude (Pico Rengifo) of approximately 5500 feet. Its northern end is bounded by a loop of the upper Rio Giiejar and is less than one hundred miles south of Bogota, and about sixty miles south and a little west of Villavicencio. A low neck of land about seventeen miles wide, extending from the northwestern corner of the Sierra Macarena to the foothills of the Sumapaz Massif (14,960 feet) of the Cordillera Oriental, is the only visible connection with the Andes. Geological studies have shown that the proximity of the Maca-rena to the Andes is misleading, as the former evidently is not an offshoot of the latter but is related instead to the more or less iso-lated hills and mountains to the eastward. These are believed to be remnants of a great plateau, the so-called "Guiana shield" or sand-stone table-land, that formerly extended across Venezuela and British Guiana to Surinam. Both zoological and botanical investigations in representative areas from the Andes to the Guianas appear to cor-roborate this premise. As will become evident beyond, the avifauna of the Sierra Macarena is predominantly that of the eastern lowlands and includes relatively few birds with Andean affinities. Further clarification of faunal relationships in the area has now become pos-sible as the list of Sierra Macarena species treated below is more complete than any other yet published. The first zoological reconnaissance of the Sierra Macarena was undertaken during the winter of 1941-42 by an expedition of the American Museum of Natural History led by E. Thomas Gilliard (1942). In a period of little more than two months, and working Library of Congress Catalog Card Number: 62-18133 No. 952 69 muwunriFTNE OCT 1 3 1962 NATURAL ^M-1 1 ]%2 HISTORY SURVEY WflBin 9f IUUmI LIBRARY
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