Newspaper article The Christian Science Monitor

Requiem for the Songbird: Perilous Decline Puzzles Scientists the Migratory Birds Are Dropping in Number, but Observers Disagree on Scale of the Problem

Newspaper article The Christian Science Monitor

Requiem for the Songbird: Perilous Decline Puzzles Scientists the Migratory Birds Are Dropping in Number, but Observers Disagree on Scale of the Problem

Article excerpt

High in a California live oak, a Wilson's warbler - a small, yellow-green songbird with a glistening black cap - engages in a ritual of spring. The warbler belts out his sharp, staccato song. "This is my territory," he is saying, beckoning a female to join his leafy kingdom.

With equal ritual, Julian Wood, a young biologist, carefully notes the call and its location. Around him, among the scrub brushes and stands of oak and pine on this bluff above the Pacific Ocean, stakes carefully demarcate sections in which scientists keep count of every breeding pair of birds.

For 30 years, scientists here at the Palomarin field station of the Point Reyes Bird Observatory have been counting and studying the breeding birds. But since the 1980s, scientists here, as elsewhere, have grown alarmed at what their studies are showing - widespread and significant declines in the numbers of neotropical migratory birds. These birds winter in the tropics of Central and South America and breed in the northern part of the hemisphere. Hardest hit are songbirds - sparrows, warblers, orioles, and other denizens of river basins, grasslands, and forests. Often invisible to the eye, their lilting burbles fill the early morning air. "A half a dozen years ago, when news of the declines hit the scientific world and the public, people were aghast," says Peter Stangel of the National Fish and Wildlife Foundation. "A lot of birdwatchers knew something was wrong, but they did not know the scale of the problem." The numbers can be dramatic. Of 30 songbirds that breed at the Palomarin field station, 17 species are in significant decline. The Wilson's warbler population has dropped by almost 10 percent each year over the past 15 years, while farther inland, in California's Central Valley, the species has virtually stopped nesting. "These birds are getting hammered," says Daniel Evans, executive director of the Point Reyes Bird Observatory. "Migration as we know it is going to disappear in our lifetime." But scientists debate both the scope and the causes of the problem. While the specifics may vary depending on the species, most point to habitat loss at both ends of the migratory path due to development as a major reason for the declines. Northern forests have been fragmented by the sprawl of suburban development, while tropical rain forests have been wiped away to make room for cattle ranches in Mexico and Central America. In the breeding grounds, changes in habitat have most severely affected birds that nest in grasslands and scrub, says biologist Sam Droege. In the West and Midwest, grassland species such as sparrows, meadowlarks, and bobolinks have been severely affected by farming techniques including the use of herbicides and pesticides. In the East, birds that nest low to the ground in young trees and scattered bushes, such as yellow-breasted chats and white-eyed vireos, are vulnerable to a proliferation of predators, including house cats, raccoons, and possums. …

Search by... Author
Show... All Results Primary Sources Peer-reviewed

Oops!

An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.