Think this spring has been tough? Consider the songbird

Swallows that survived the bad spring weather make their nests under the eaves of a building at Carlos Avery Wildlife Management Area.
MPR Photo/Stephanie Hemphill

In the Twin Cities, temperatures in April were two-point-six degrees below average. And we got nearly an inch more precipitation than usual for April -- a pattern that's continuing so far this month.

And then there was that blizzard. Two weeks ago, we were treated to one of the heaviest late-season winter storms in recent memory, according to the Minnesota Climatology Working Group.

Up to 15-inches of snow fell in places in Minnesota. The Park Rapids area posted all-time records for April snowfalls.

To find out how all this nasty weather is affecting migrating songbirds, we tracked down Carrol Henderson, with the Minnesota DNR's non-game wildlife program.

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He came out of a budget meeting at the Carlos Avery Wildlife Center near Forest Lake, and we chatted at a picnic table outside.

As we talked, swallows were swooping through the air and tending to their nests in the eaves of buildings at the center. But these birds are the survivors.

Carrol Henderson says people have been calling his office from all over the state to report finding dead and dying tree swallows and bluebirds.

Carol Henderson
Carol Henderson, with the DNR's Nongame Wildlife Program, has been hearing from people all over the state who have found dead songbirds, because of this year's late spring.
MPR Photo/Stephanie Hemphill

"Normally we would have some insects emerging in the latter part of April, and that would comprise the diets for these birds like swallows," Henderson says. "But when the temperatures were so cool the insects did not emerge, and then when the snow came, it really put a heavy damper on their survival. So we got calls from people who were actually watching swallows die in little groups on the ground; other swallows and eastern bluebirds were found dead in their nest boxes."

Henderson says purple martins and yellow rumped warblers were also affected.

Calls came from the Twin Cities north to Brainerd, Fergus Falls, and Bemidji.

"This hasn't happened in recent years, but with Minnesota weather being what it is, this is always a possibility," Henderson says. "Some birds get ahead of the weather patterns, and then when cool weather or a spring blizzard happens we can have some mortality like this, and it's just a part of nature."

Henderson says he wouldn't attribute the phenomenon to global warming.

"What we're seeing here is a quirk of Minnesota weather -- a late, cool spring and a late very heavy snow that limited the ability of the birds to forage naturally for the foods they need to survive."

And the good news is it shouldn't affect the long-term survival of the various species.

"They do have a very high reproductive potential, so if they have a bad year once every few years, they should be able to bounce back."

"It was probably a very spotty impact," Henderson says. "Other birds will be migrating in somewhat later, so I think the bulk of our bird populations will still be okay. In terms of the tree swallows and bluebirds, they do have a very high reproductive potential, so if they have a bad year once every few years, they should be able to bounce back."

Henderson says there's not much people can do to help the birds.

"We do appreciate getting reports about this, though, because this helps us understand the weather patterns and their impacts on wildlife, and when we get calls from around the state it helps us get a better idea of the big picture of how these things are affecting wildlife."