As Minnesota's wetlands and grasslands are lost to farms and homes, once-common birds such as meadowlarks and red-headed woodpeckers are suffering dramatic population declines, according to Audubon Minnesota.
In a nationwide analysis of bird populations by the National Audubon Society, the state chapter Thursday highlighted species with especially large losses in Minnesota over the past four decades. Populations of western and eastern meadowlarks, red-headed woodpeckers, purple martins, northern pintails and Indigo buntings all dropped between 62 percent and 95 percent since 1967, the chapter said.
"It's a fair assumption that habitat loss or degradation would be the No. 1 cause,'' said Mark Martell, Minnesota Audubon's director of bird conservation. "We know we are losing grasslands. Habitat is a big issue. But the environment is under a lot of other stresses. We've got invasive species coming in and pesticide problems.''
The report also noted emerging threats, such as global warming and demand for corn-based ethanol.
The bird group compared databases for 550 species from two different bird surveys: its own Christmas bird count and the U.S. Geological Survey's breeding bird survey in June.
"One of the things this report is saying is something is wrong, we are losing common birds, we better figure out why, and we better take some action quickly,'' Martell said.
Of the 20 species on the national list showing the steepest declines, 16 can be found in Minnesota. They include evening grosbeaks, boreal chickadees, American bitterns and ruffed grouse.
Audubon Minnesota said birds hit especially hard here are faring poorly for a variety of reasons:
Martell and Mark Peterson, director of Audubon Minnesota, said people can make a difference by protecting habitats and providing landscaping for wildlife.
"We clearly are not doing what we need to do in terms of managing our resources,'' Martell said. "A lot of actions people can take in their daily lives make a difference - pesticides on your lawn, bird-friendly plantings on properties. The daily decisions 5 million people are making do add up and do make a difference.''
Nationally, 20 common bird species - those with populations more than half a million and covering a wide range - have seen populations fall by at least in half since 1967, according to the study.
Some, such as the evening grosbeak, used to be so plentiful that people would complain about how they crowded bird feeders and finished off 50-pound sacks of sunflower seeds in just a couple days. But the colorful and gregarious grosbeak's numbers have plummeted 78 percent.
"It was an amazing phenomena all through the '70s that's just disappeared. It's just a really dramatic thing because it was in people's back yards and (now) it's not in people's back yards," said study author Greg Butcher, Audubon's bird conservation director.
Audubon Board chairman Carol Browner, former U.S. Environmental Protection Agency administrator, called the declines "a warning signal.''
"We are concerned. Is it an emergency? No, but concerns can quickly become an emergency,'' Browner said.
Compared with 1967, there are 432 million fewer birds of these species, including the northern pintail, greater scaup, boreal chickadee, common tern, loggerhead shrike, field sparrow, grasshopper sparrow, snow bunting, black-throated sparrow, lark sparrow, common grackle, American bittern, horned lark, little blue heron and ruffed grouse.
The northern bobwhite had the biggest drop among common birds. In 1967, there were 31 million of the plump ground-loving bird. Now they number closer to 5.5 million.
But while these common birds are in decline, others are taking their place or even elbowing them aside. The wild turkey population, once in deep trouble, is growing at a rate of 14 percent a year. The double-crested cormorant, pushed nearly to extinction by DDT, is growing at a rate of 8 percent a year and populations of Canada geese increase by 7 percent yearly.
Many birds that are disappearing are specialists, while the thriving ones are generalists that do well in urban sprawl and all kinds of environments, Butcher said.
"The robins, the Carolina wrens, the blue jays, the crows, those kinds of birds, are doing just fine, thank you," Butcher said. "They really get along in suburban habitats, most of them even like city parks, so they are not as susceptible to the human changes in the environment.''
Dennis Lien can be reached at email@example.com or 651-228-5588.
The Associated Press contributed to this report.
Meadowlark, western and eastern: 95 and 68 percent
Red-headed woodpecker: 89 percent
Purple martin: 78 percent
Northern pintail: 77 percent
Indigo bunting: 62 percent
Grasshopper sparrow: 98 percent
American bittern: 88 percent
Field sparrow: 71 percent
Eastern meadowlark: 70 percent
Whip-poor-will: 47 percent