A rare sequence of spring snowstorms across the northern Great Plains is causing difficulties and even starvation for some migratory birds.

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© Eric Landwehr, South Dakota State University
Birds that normally winter in the Dakotas, like this Junco hyemalis, are having a tough time scavenging for food as winter refuses to end, even in April.
While it's not unusual to get a single snowstorm in April, the weekly storms during late March and the first half of April are taking their toll on wildlife, according to bird expert Kent Jensen of South Dakota State University.

He and others beneath North America's Central and Mississippi migratory "flyways" have found dead robins in their backyards, with the birds emaciated and even having burned up their breast muscles for nutrition in a last-ditch effort to survive.

"The ground to the north in North Dakota and Canada is still frozen, and we're only getting occasional thaws that allow the birds to feed from the ground here in eastern South Dakota," Jensen tells Earthweek.

He said many species are holding back far to the south, but the early-arriving robins have been forced to eat the wax coating of cedar berries to keep their fat supplies up.

Frozen lakes are also holding back migratory waterfowl, which could mean they are using up energy during their unplanned layover that they need for successful breeding this summer, Jensen says.

The fat supplies those birds need for laying eggs high in the Arctic is also being depleted as the birds hold back to the south, waiting for spring to finally arrive.