Easing the Travails of Migratory Birds

摘要

Every May, people throughout the Western Hemisphere celebrate International Migratory Bird Day with events marking either the return of migrating birds to their breeding grounds or their departure from their winter ranges. Special attention has been given to a group of approximately 300 species, known as neotropical migrants, that breed in the temperate areas of North America and winter in the Neotropics of Central and South America and the Caribbean. Scientists and conservationists are particularly concerned because about one-third of these species have been declining in numbers during the last 30 years and neither the underlying causes nor the appropriate remedies are entirely clear.