The lark bunting, Colorado’s state bird, is among the dozens of bird populations disappearing from skies and grasslands, according to a national study released Thursday.
Five species of common birds in Colorado were found to be in serious decline, according to the analysis by the National Audubon Society.
“The issue is one of grasslands’ being impacted by suburbanization,” said Gary Graham, executive director for Audubon Colorado.
Among other Colorado birds dwindling in numbers are the north harrier, with a nearly 77 percent decline since 1967, and the horned lark, down 72 percent, the study said.
The lark bunting is down 64 percent in 40 years.
“Four of the five species we list are associated with grasslands,” Graham said.
Those grasslands, Graham said, are under pressure as more people move to the Eastern Plains, leading to new housing developments, new roads and new transmission lines.
In addition to sprawl, new agricultural techniques have led to more intensive land use.
“Historically, land was left unused,” Graham said, offering habitat for birds.
These trends, coupled with drought, Graham said, have led to the declines.
Growing suburbs, shrinking habitat and invasive species are having an effect on bird populations across the country, according to the Audubon report – “Common Birds in Decline.”
Northern bobwhite populations, in Wisconsin, Michigan and New York, are down 82 percent because of loss of habitat.
Expanding agricultural activity is cited for a 78 percent decline of northern pintail populations in the continental United States.
“These are not rare or exotic birds we’re talking about – these are the birds that visit our feeders and congregate at nearby lakes and seashores,” said Audubon chairwoman Carol Browner. “Their decline tells us we have serious work to do.”
Audubon researchers said, however, that none of the 20 species in the study were in immediate danger of extinction.
Another factor affecting birds is poor forest management, Graham said.
Colorado’s evening grosbeak populations have seen a 95 percent decrease because of logging, mining, drilling and development, the report said.
Rufous hummingbird populations, found in the Pacific Northwest, join grosbeaks with a 58 percent decline because of logging and development, according to the study.
Global warming, the report noted, is also playing a role in the decline.
“There’s a lot of concern about global warming, which will change habitats and exacerbate the problems that animals are having,” Graham said.
Snow buntings, which breed in Alaska and northern Canada, are suffering from the loss of fragile tundra habitat as warming alters and disrupts the Arctic’s delicate ecological balance, the study said.
By focusing on common birds, Graham said, the report is also telling “us something about our own environment and quality of life.”
“Water quality and air quality declines as landscapes decline,” he said, “as well as our quality of outdoor experiences.”
Staff writer Simona Gallegos can be reached at 303-954-1555 or sgallegos@denverpost.com.
