Nearly 3 billion fewer birds exist in North America today than in 1970.
While scientists have known for decades that certain kinds of birds have struggled as humans (and bird-gobbling cats) encroach on their habitats, a new comprehensive tally shows the staggering extent of the loss. Nearly 1 in 3 birds — or 29 percent — has vanished in the last half century, researchers report September 19 in Science.
“Three billion is a punch in the gut,” says Peter Marra, a conservation biologist at Georgetown University in Washington, D.C. The loss is widespread, he says, affecting rare and common birds alike. “Our study is a wake-up call. We’re experiencing an ecological crisis.”
Looking at the loss of individual birds sets this study apart, says Hillary Young, an ecologist at the University of California, Santa Barbara who was not involved in the study. “So much of the focus in conservation is on the loss of species,” but individual birds play an important role in ecosystems, pollinating plants, dispersing seeds and controlling pests.