The Challenge of Finding Food in Winter
by Laura Erickson
Imagine eating frozen meat without using your teeth. That’s something Bald Eagles do often in the winter.
When water is open in a good fishing river, of course, eagles don't have to worry about crunching through ice, either on the water’s surface or in their food. Even when the air temperature is 20 below zero, open water cannot be colder than 32 degrees Fahrenheit, so fish may be cold, but they’re not frozen.
But eagles don't live on fish alone, especially in the winter. In northern areas, eagles are often seen eating road-killed carcasses. During a cold spell, how can they possibly eat rock-hard, frozen meat?
Ravens and wolves are usually the first to dine on a carcass. Ravens use their massive but straight, pointed beaks to hack away. Some carcasses are small enough to hack just anywhere, but some are just too thick. A sturdy deer hide is hard to break through even when the deer isn't frozen. So ravens usually eat a deer from the inside out, pulling out the guts from the opening under the tail. Once ravens start pecking at the carcass with their beak, nearby eagles can pick up and swallow flying chips of meat. And on sunny days, even when it's very cold, the inside of the deer will be warmer than the air, and is often not solid, so eagles can rip off chunks of the guts when the ravens pull them out.
Wolves gnaw their meat, and sometimes “play tug-of-war” while fighting over larger pieces, which helps to break them down into more chewable sizes. Again, Bald Eagles can take advantage of chunks they find.
Eagles have other ways of finding food in winter. For instance, I’ve seen them hunting for mice in a field. And sometimes eagles find their food thanks to humans. When people are ice fishing, they often leave the fish sitting out on the ice to keep them fresh rather than bringing them inside their warm fishing huts. Sometimes eagles notice this and fly in to steal the fish the moment the anglers are back inside their huts! Some eagles come down to bait pots and take out minnows.
The oddest winter eagle feeding strategy I’ve ever heard of was from a man in Port Wing, Wisconsin. He attracted a Bald Eagle to his bird feeder! Every morning the man set out a couple of hard-boiled eggs, and the eagle flew down, ate the eggs, and flew off again.
Try This! Scavenger Hunt for Eagle Food
Write a list of eagle winter food items for a “scavenger hunt” game. Which of the items on your list can you find in one day? An eagle eats 5-10% of its body weight each day. Do you think you could find that much food on your hunt? (First, find out what an average eagle weighs.) How much food would you need in a day if you were to eat the same percent of your weight as an eagle eats?
National Science Education Standards