© U.S. Fish & Wildlife ServiceThe Evening Grosbeak, common to the western U.S. and Canada, has seen a 78 percent decline since 1967 according to the Audubon.
A new study recently released by the non-profit National Audubon Society found that since 1967, the average population of many common bird species has fallen by 68 percent, with some individual species declining as much as 80 percent. In all, the 20 species on the group’s national Common Birds in Decline list lost at least half their populations in just forty years.
Greg Butcher, who authored the study for the group, blames a combination of suburban sprawl, climate change and invasive species. "Most of these we don’t expect will go extinct," he told reporters. "We think they reflect other things that are happening in the environment that we should be worried about."
The findings were culled from the group’s analysis of four decades" worth of data collected by its "citizen scientists" who participate in its annual Christmas Bird Count and Breeding Bird Survey programs.
For its part, Audubon is calling on individuals to take action to reverse the trend by protecting local bird habitat, promoting sound agricultural policy, reducing one’s own carbon footprint and warding off invasive species without resorting to harmful pesticides and herbicides.