Peru Field Guides Page 3

Body mass, or weight, is the most useful descriptive measure of relative body size in birds. Masses are usually reported in avian studies of comparative ...

A unique field guide and reference, Where to Watch Birds in South America is designed to help the avid birder and the general wildlife enthusiast organize ...

This reference guide gives general details about the swallows and martins of the world. These include appearance, the basic coloration and differences between the sexes and ...