B.A. Dowell D.K. Dawson R. Coates-Estrada J. Colon F. Espinoza J. Rodriguez R. Sutton T. Vargas Dieter Weyer Humberto Alvarez-Lopez Gustavo Kattan Carolina Murcia C.S. Robbins 1988 application/pdf en Sociedad Vallecaucana de Ornitologia, Universidad del Valle Comparisons of winter bird populations in extensive neotropical forest and in isolated fragments chapter