More Eagle Updates
From the MN DNR
Eagle Nest Update: February 10, 2017
And then there were three
True to form, our eagle pair laid their third egg two days after the second egg. Egg number one arrived on Saturday, Jan. 28; the second egg came on Tuesday, Jan. 31 and the third egg appeared on Friday, Feb. 3. Looking ahead about 35 days, we should start watching for a hatch around March 3. We’re looking forward now to a full month of watching this diligent pair switch off incubation duties and bringing new culinary surprises into the nest.
We’ve received some questions about the color of the third egg. Why is it so bright compared with the other two? This is normal color variation, according to the Raptor Center of Minnesota; it’s no cause for concern in terms of development or shell thickness. After a month of rolling around in the nest with the other two, the odd egg will likely be the same color as the other two by hatching time.
Minnesota weather also has been true to form, changing dramatically from one day to the next. Temperatures this week at the nest have gone from 0 degrees Fahrenheit to almost 40 today. We saw snow and freezing rain on the ground — and on the eagles this week. Weather for the week ahead is expected to be mild, good for hunting and good for incubating.
Winter breeding is for the birds!
Did you ever wonder why bald eagles breed during the winter? It’s sure not because it’s easy! Incubating eggs and finding food for hungry mouths is hard work, especially when temperatures are frigid, daylight is scant, and everything’s covered with snow and ice.
One explanation for the species’ winter breeding may pertain to the “biological head start” it affords eaglets. Earlier breeding means earlier eggs, earlier hatching, and earlier fledging or nest departure. That provides more time for eaglets to practice their flight and foraging skills before fall migration and the onset of the next winter.
Although most birds breed when temperatures are mild and food is abundant, the bald eagle isn’t the only winter breeding bird in Minnesota. Other winter breeders include the great horned owl and rock pigeons (although pigeons have the ability to produce multiple clutches of eggs throughout the year).
As winter progresses and temperatures rise, more and more species begin breeding. Common ravens, barred owls, and house sparrows breed during late winter or early spring. Then, when spring begins overshadowing the rawness of winter, species like hairy and pileated woodpeckers and American woodcock begin their breeding preparations.