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1/7/2019 10:45:00 AM
Warm winters, early springs threaten Indiana birds, says Robert Cooper Audubon Society official

Christopher Stephens, Herald Bulletin

ANDERSON – As Hoosier winters continue to remain warmer and the start of spring becomes unpredictable, research suggests climate change threatens Indiana songbirds.

While climate change will increase the world’s average temperature year-over-year, climatologist also warn the warming can have a serious disrupting effect on animal and plant life – particularly migratory birds who rely on clockwork-like cycles to dictate when they leave and return.

And this year, with 50-degree temperatures in mid-January, is likely to affect a whole host of species, said Savannah Lundgren, education chair at the Robert Cooper Audubon Society

“We have a lot of birds that aren’t in Indiana right now, and what’s going to happen is they are not going to leave their wintering grounds until the conditions there become unfavorable,” Lundgren said.

In previous years this works, allowing the birds to feed on year-round plants in the South while their breeding grounds in Indiana are snow-covered and far too chilly.

But when winter stays warm or spring comes too soon, the usually dormant plants and insects that feed the birds come back sooner. And while that means a feast for the birds that stay in Indiana all year – it means slim pickings for the state’s returning songbirds.

“What is happening is a lot of our songbirds and wood warblers are staying down South for too long, when they come back into Indiana the other birds have already gotten to the food and started mating,” Lundgren said.

And without food, the birds that make a hike through Indiana’s woodlands must suffer.

It’s a problem not limited to Indiana. Research released by the U.S. Geological Survey in September showed changing seasons are changing migration habits and threatening hundreds of species.

Eric Waller, a research scientist for USGS and lead author of the study, wrote that birds rely on things like day length to determine when seasons are changing. But as climate change disrupts those cycles, while day length remains constant, birds get mixed signals to determine when to migrate.

The researchers used climate and refuge data from the U.S. Fish and Wildlife Service reaching as far back as 1900 and also studied the migratory patterns of the endangered whooping crane and the blue winged warbler.

They paired that with information collected by the USA National Phenology Network, a group that collects seasonal natural data from thousands of volunteer observers and science agencies across the country.

The researchers found spring is arriving earlier across most of North America, and birds are reading shifting seasonal patterns like day length, plant buds and blooms, insects hatching and higher temperatures as a sign to migrate – which can lead to bad readings by birds.

The study suggests that, on average, spring arrived three to six days earlier across all the migratory routes. 

Along with giving non-migrant birds a first chance at food – changing seasons that vary across the U.S. differently can also mean groups of the same bird species can cease to breed together – resulting in genetic drift.

Lundgren said to imagine two groups of wood warblers living at Mounds State Park. When they are at Mounds they interbreed, but when they go south for the winter one group goes to Alabama and the other goes to Tennessee – where each group gets different signals on when to return.

“The ones that they got signal to come up early they will breed together, the ones that get later will breed together … what you see over time is genetic drift – which could cause new speciation,” she said. “We saw this with the black capped and Carolina chickadee. They once were one species but then split apart.”

But while it will take massive international regulation to slow or stop climate change, Lundgren said there are a few things Hoosier bird lovers can do to help out.

“Make sure that if you were to give out bird seed, just help feed the birds when they get here. … April and May are great times to start … but because it’s getting warmer maybe start putting out feed in March,” she said. “If you are doing it anyway, you might as well change to when the birds are coming back.”

After all – it’s not just beautiful bird songs that will suffer if the state’s songbird populations decline.

“But what they do for us is they get rid of a lot of pests for us, not just mosquitoes and gnats, but things we don’t think about like the worms and the gross insects that are inside trees and plants that hurt them,” she said. “If the birds weren’t around, just imagine how bad it will be for our ecosystem because the animals weren’t here to eat the pests.”

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