Biologist Dan Reinking said he still runs into folks from time to time who recall the sight of prairie chickens on opening day of the hunting season.
“They recall the glory days when they would go out to John Dahl (Wildlife Management Area), and they talk about how the sky opened up with prairie chickens flying everywhere. That was just a few decades ago,” he said.
Reinking and other Oklahomans who have tracked bird populations for decades were not surprised that a recent study by a team headed by Kenneth V. Rosenberg of Cornell Lab of Ornithology that showed North America’s breeding bird populations have decreased 29 percent overall since 1970.
They also note that Oklahoma will play a key role in the future as a prairie state, with the study showing big declines in common grassland birds such as sparrows, blackbirds and meadowlarks — and, of course, prairie chickens. Part of the battle ahead may come right into people’s backyards.
Instead of a focus only on birds nearing extinction, the study points out a loss of nearly 3 billion breeding birds. In other words, more than a quarter of the continent’s population of birds has been lost in a half century; one in four breeding birds come springtime.
Most are from groups considered “common” or “abundant.” More than 90 percent of the total cumulative loss can be attributed to 12 bird families, including warblers, blackbirds, finches and sparrows (not “house sparrows,” which are an invasive finch species), according to the study.
The study looks at numbers and not causes but does mention such things as urban sprawl, cats, use of pesticides and herbicides, and habitat loss. Climate change may be part of the picture, and recent studies have shown a broad loss in abundance of insects worldwide that birds rely upon for food.
“It gets complicated looking at all the different factors,” said Scott Loss, assistant professor in the Oklahoma State University Department of Natural Resource Ecology and Management.
“We have a grand challenge going forward. This has the potential to be another ‘Silent Spring’ moment,” he said in reference to Rachel Carson’s 1962 book that is widely credited for the birth of the modern environmental movement. “We’ve drastically changed the number of birds and on a widespread scale.”
The study crossed Loss’ wheelhouse because he studies global change ecology management — which isn’t just global climate change but things such as urban sprawl and pesticide use, essentially any factors that create conflicts between humans and wildlife, he said.
“Things like birds colliding with glass, which happens across the entire landscape with large buildings in Oklahoma City and Tulsa but also at our homes,” he said. “Another big threat is free-ranging and pet cats. … It’s studying on a more local scale to understand how to manage those factors.”
Among birds listed as declining are many familiar in Oklahoma backyards, including American robins, down 20 million; northern cardinals, down 11 million; nuthatches, down 7 million; and red-winged blackbirds, down more than 90 million. Good news for Oklahoma’s state bird, the scissor-tailed flycatcher, is that its numbers are down a relatively slight factor, only 2.3 million.
“A lot of it is huge losses of abundant species,” Loss said. “Even if they are still a commonly seen bird, losing a huge number of them can be impactful.”
Scissor-tailed flycatchers likely are doing better because they are adaptable, he said. “You’ll see them nesting on power poles next to a shopping mall.”
Reinking, a senior biologist at the Sutton Avian Research Center in Bartlesville and author of winter-bird and breeding-bird atlases for Oklahoma, also is coordinator of the United States Geological Survey’s annual Breeding Bird Survey for Oklahoma. Surveys from across the country contributed data for the study. Oklahoma ornithologists have done the survey since the mid 1960s, he said.
“Other than the Christmas Bird Count it’s one of our longest-running and most intensive efforts in Oklahoma,” he said. “Anyone can go to the website and look at the results and drill down to even specific routes and look at the changes over a 10-year period. … It’s color coded so you can see at a glance what are the big declines and what are the increases.”
Notable among the survey data are annual increases of 20 percent for Canada geese, 40 percent for the invasive Eurasian collard dove and 10 percent for fish crows, while orchard orioles and loggerhead shrikes are down roughly 5 percent per year and Bell’s vireo are down 2.5 percent in Oklahoma, he said.
While the Cornell study notes that the continental population of grassland birds such as the eastern meadowlark have declined nearly 50 percent continent-wide, the trend on the Oklahoma survey shows them down about 2.5 percent per year the past 10 years.
Amateur birders also fit into the study picture, and Tulsa has been home to a National Audubon Society Christmas Bird Count annually since 1926. Some of the long-term data from that count worked into the most recent study, and it also made headlines in 2009.
A 40-year analysis of the counts showed 48 of 305 common, widespread species in North America have shifted their wintering grounds more than 200 miles northward. It created additional buzz around climate change debates at the time and still is cited by the Environmental Protection Agency as a change indicator.
With 25 years running the same route for the annual Audubon Christmas Bird Count and now as Tulsa-area coordinator, Jeff Cox said the annual ups and downs are always noticed in the survey area north of Tulsa, but often it’s hard to see the bigger picture.
Long term, the things that stand out are the lack of prairie chickens and prairie songbirds, but gains of hawks and eagles and things such as white-winged doves and Canada geese have increased.
Landscape changes are obvious for the people who run the same route year after year, he said. Most noticeable are prairie or pasture areas that now are over-grazed or replaced by housing developments, Cox said.
While the Cornell study focuses on numbers and not causes, the study will inspire more scientists to look at the causes behind the declines and, perhaps, come up with solutions, he said.
There are things people can do now, but the puzzle for this wide variety of birds, many of which migrate thousands of miles overseas, likely will be more difficult.
“It’s more than just banning something like DDT,” Cox said.
A widespread issue calls for widespread changes and broad public support for conservation measures such as the Migratory Bird Protection Act and the Endangered Species Act, he said.
Everyone can do their part, even if it’s only putting items up on windows on their home to prevent collisions or keeping their cats inside, Loss said. Cats are responsible for the loss of billions of songbirds in the U.S. annually, he said.
“Generally, we know how do to it,” the Sutton Center’s Reinking said. “We know how to save birds, and we’ve done it. It’s a matter of public support and financial support and enough people to care about it to make it happen.”