When I throw bird seed onto my deck each morning I see fewer
and fewer birds in both species and numbers. Where have they all gone? Two
years ago there would be a hundred or more. Now I am lucky to see 20. There used to be many more species especially
sparrows. Now I have one, the white crowned.
In September scientists reported that the number of birds in the United States and Canada has fallen by 29 percent since 1970. There are
2.9 billion fewer birds taking wing now than there were 50 years ago.
David
Yarnold, president and chief executive of the National Audubon Society, called
the findings “a full-blown crisis.” Experts have long known that some bird
species have become vulnerable to extinction. But the new study, based on a
broad survey of more than 500 species, reveals steep losses even among such
traditionally abundant birds as robins and sparrows.
The losses
include favorite species seen at bird feeders, such as Dark-eyed Juncos (or
“snowbirds,” down by 168 million) and sweet-singing White-throated Sparrows
(down by 93 million). Eastern and Western Meadowlarks are down by a combined
139 million individuals. Even the beloved Red-winged Blackbird—a common sight
in virtually every marsh and wet roadside across the continent—has declined by
92 million birds.
“We want to
keep common birds common, and we’re not even doing that,” said Pete Marra, a
study coauthor who formerly directed the Smithsonian Migratory
Bird Center
and now directs the Georgetown Environment Initiative.
So what is
exactly going on? There are likely many causes, the most important of which
include habitat loss and wider use of pesticides. “Silent Spring,” Rachel
Carson’s prophetic book in 1962 about the harms caused by pesticides, takes its
title from the unnatural quiet settling on a world that has lost its birds:
“On the
mornings that had once throbbed with the dawn chorus of robins, catbirds,
doves, jays, wrens, and scores of other bird voices, there was now no sound.”
Forest-dwelling birds, which are more abundant, lost one billion individuals. Shorebirds, which traverse across full hemispheres during migration, are “experiencing consistent, steep populations loss” at a rate of 37 percent in less than 50 years.
“Declines in your common sparrow or other little brown bird may not receive the same attention as historic losses of bald eagles or sandhill cranes, but they are going to have much more of an impact,” said Hillary Young, a conservation biologist at the University of California , Santa Barbara .
Among the
worst-hit groups were warblers, with a population that dropped by 617 million. Vireos which share
the same habitat are thriving and no one knows why.
There are 440 million fewer blackbirds than there once were. Even starlings, a species that became a fast-breeding pest after its introduction to theUnited States
in 1890, have dwindled by 83 million birds, a 49 percent decline. Europe is experiencing a similar loss of birds, also
among common species.
There are 440 million fewer blackbirds than there once were. Even starlings, a species that became a fast-breeding pest after its introduction to the
Scientifically
speaking, birds are considered indicator
species, or animals used to infer the health of an entire ecosystem.
They are worldwide “canaries in
the coal mine,” which refers to the 20th-century practice of
carrying caged birds into mines to detect toxic gases before humans suffer harmful
effects.
Roger Tory
Peterson called birds “an ecological litmus paper.” They are crucial to the health of
many ecosystems, and their populations anticipate the health of whole
environments.
While all of this is bad news, researchers
found some positive signs. Bald eagles are thriving, falcon
populations have grown by 33 percent and waterfowl are on the upswing.
Many recovering
bird species that were nearly wiped out in the last century by pesticides, hunting
and other pressures have been saved by conservation. This shows
that we have the power to save other species.
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