A Birder’s Guide To The Future [Infographic]
Land use and climate change are turning some birds into winners, and others into losers
Climate models predict a much warmer world in 60 years, with flash storms and extended droughts. But they don’t take into account changes to the land, like urban development, agricultural expansion, or resource extraction. “You’re missing a very large part of the story if you don’t look at the impact of land-use change,” says Terry Sohl, a U.S. Geological Survey researcher. Sohl is the first to publish a study combining climate research and high-resolution land-use data into a single model–in this case, to advance bird research. It shows how each species’ U.S. range–the area where it can be found–will change by 2075. “Different species will respond to these shifts in different ways,” says Wesley Hochachka, an ornithologist at Cornell University. “Some are tied to specific vegetation; some get along with humans; some are going to move. There will be winners and losers.”
The elusive Baird’s sparrow has a small range, very specific moisture requirements, and an intolerance to fluctuating temperatures. Unfortunately for the bird, climate change will mess with all three. Although its range loss here appears dramatic, that’s likely because the species will be moving north into Canada, beyond the geographic scope of this study.
While a shifting climate brings bad news for the grasshopper sparrow, land-use changes will offset much of its range loss. These birds actually stand to benefit from people swapping forests for farmland. The sparrow makes itself at home in pretty much any open grassland, which is exactly what new croplands and hay fields in the eastern U.S. provide.
The hooded warbler won’t see much net difference in its range due to climate change–it will gain as much as it loses. The primary driver here is forest loss caused by urbanization and agriculture, such as tree farms in the Southeast. Since these pine fields are clear cut every 20 years, the ecosystems don’t function like the mature forests the warblers require.
The gray vireo, for one, will celebrate a hotter, drier future. In the high plains and desert mountains of the American Southwest, this small songbird makes itself at home among all types of shrubs and scrub brush, where it hunts bugs and builds nests. As arid conditions spread farther out, the vireo’s preferred vegetation will also proliferate.
2,319,910: Number of U.S. bird observations that Sohl sifted through to make the models for this study.
Sex-Deprived: Sharp-Tailed Grouse
Males are known for their flamenco-like mating dance, for which they favor a very particular stage: an undisturbed, gently sloped hilltop with short (but not too short) vegetation that gives females a clear view. Frequent industrial hay harvests now jeopardize these critical mating grounds.
Indifferent To Us: Great Horned Owl
Some species thrive by not being picky eaters. Great horned owls will go after anything they can find, including small mammals, reptiles, and even other birds. In fact, as long as there are enough places to nest, these owls don’t seem to mind human company.
New Survival Tactics
As species move into different regions, they’ll have to interact with new neighbors. In South Dakota, for example, northern mockingbirds are encroaching on brown thrasher territory. Soon they’ll be competing for the same resources. Timing is an issue too. A European bird study found that species that began migrating earlier enjoyed stable or growing populations, while birds that stuck to the usual timetable saw declines. But the early birds face risks too. In response to warming temperatures, a species called the great tit has started laying its eggs sooner. Chicks hatch about 10 days before their primary food source, caterpillars, emerge. That’s a problem. For the nonmigrators, behaviors may need tweaking. A study of the grey shrikethrush in southeastern Australia found that the roadside-dwelling bird chirps at a higher frequency amid cars to ensure that its mating song can be heard over traffic.
This article was originally published in the April 2015 issue of Popular Science, under the title “A Birder’s Guide to the Future.”