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Why do bald eagles choose winter as the time to start a family?

DNR's EagleCam shows how birds of prey thrive in winter
DNR's EagleCam shows how birds of prey thrive in winter 02:30

ST. PAUL, Minn. – One of the most popular glimpses into nature's wonder is in full swing.

The Minnesota DNR EagleCam is getting a lot of attention. Especially last week, when the mother was draped in snow as she kept two eggs warm. Sadly, one of those eggs later broke.

Winter is a brutal season in Minnesota, but it's also the perfect time for these majestic birds to start a new family.

If there's anyone who knows why our nation's fierce and beautiful bird would weather such conditions while protecting its future young, it's our friends at the University of Minnesota Raptor Center. Lori Arent is the center's assistant director.

"From the time the egg is laid until the time that a young eagle fledges is about four months, and so the eagles time it so that by the time those youngsters fledge, prey will be abundant as they're learning how to hunt, so they'll have a better chance of thriving," Arent said.

Their main food source is fish, which becomes much easier to catch in May and June. But not all bald eagles in the United States follow the same timeline. While those in the northern half of the U.S. start laying eggs around January, bald eagles in the south begin as early as October.

"So when you get into those hot temperatures and humid climate down in the southern United States, these eagles want to make sure that they raise their chicks, and that the chicks fledge before that intense heat starts," she said.  


No matter the region, it's easier for bald eagles to keep their eggs and young warm in cold temperatures, versus keeping them cool in hot temperatures. In fact, bald eagles in the Upper Midwest are bigger than their southern counterparts, allowing them to better conserve heat.

"And that's really important if you're gonna be incubating eggs," she said.

Which is primarily done by the female. It has what's called a brood patch, or an area on its stomach without feathers.

"So her hormones help her to lose those belly feathers, and then it gets engorged with blood, so there's a lot of heat there to keep those eggs warm," she said.

Centuries of evolution have allowed this majestic raptor to adapt and thrive in the bold north, adding to its legacy of strength and independence. 

The remaining egg in the nest should hatch sometime later this month.

To watch the DNR's EagleCam, click here.

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