Ask a naturalist – Eager for eagles

An adult bald eagle (Haliaeetus leucocephalus) calls to its chick on their nest near Puyallup, Washington. The size of the nest dwarfs both of the birds. Bald eagle nests rank as the largest nests of any bird, with a typical diameter of six feet (2 meters) and a height of three feet (1.5 meters). Some bald eagle nests way more than two tons.

An adult bald eagle (Haliaeetus leucocephalus) calls to its chick on their nest near Puyallup, Washington. The size of the nest dwarfs both of the birds. Bald eagle nests rank as the largest nests of any bird, with a typical diameter of six feet (2 meters) and a height of three feet (1.5 meters). Some bald eagle nests way more than two tons.

Q: How can I spot a bald eagle’s nest?

Most people find bald eagles fascinating to watch. Their impressive size makes them the largest raptors in Minnesota, with a wingspan of 6 to 7.5 feet! The adults have a stately appearance with the famous “bald” (actually white) head and matching tail feathers, which contrast dramatically with their dark brown body. They are skilled hunters, majestic flyers, dedicated parents and remarkable nest builders.

So how do you spot an eagle’s nest? Luckily, compared to most bird nests, they’re pretty easy to find since they are so big. Bald eagle pairs build the largest nest of any bird. Bald eagle nests average 4-5 feet in diameter and 2-4 feet deep, and are built of sticks woven together plus softer materials like grass and other flexible plants. A final soft lining, including moss and feathers, provides a safe environment for the chicks.

Bald eagles tend to choose nesting sites near water, and usually pick the tallest living tree with accessible branches. The nest is built, near the trunk, in the fork of a large branch that will provide support for the huge nest. Bald eagles generally mate for life and build the nest together. They return to the same nest each year, adding material to it as part of their pair bonding ritual. Sometimes however, a pair will abandon a nest if they have not been successful raising chicks at that site.

Although they nest early, eagles are still taking care of their chicks in May and will continue throughout the summer. The female lays 1-3 eggs in mid-February to early March, and incubates them, with some help from the male, for about 35 days until the eaglets hatch. The eaglets remain in the nest for the first three months and are fed scraps of meat from their parents until they are ready to fly. Eaglets fledge (get their flight feathers) when they are 10 to 12 weeks old, by which point they are nearly adult sized. Parents continue to care for the eaglets post-fledging as the juveniles learn to fly and hunt, which can take up to an additional three months.

For the first four years of their life, young eagles look quite different from adults and it can make identification challenging. At first they are dark brown all over, including their eyes and beaks. Throughout the second and third year their white and brown coloring will fluctuate. Finally by their fifth year, they have the characteristic coloring of an adult. Often people will mistake a juvenile bald eagle for a golden eagle, but golden eagles are quite rare in Minnesota.

The Mississippi River is a great place to look for eagles and eagle nests. The river provides a constant source of water and fish, and mature trees for nesting along its banks. The open water may also provide a better view of eagles’ nests than in a forest. Minnesota has the largest bald eagle population in the 48 contiguous states, and many eagles live in the Twin Cities. Nesting eagles are territorial and will defend their territory from other eagles. The size of the territory depends on the food resources available. In areas with a lot of food, eagles’ nests could be as close as one mile apart. Bike along the trails of the Mississippi River and look for eagles or even rent a kayak through Paddleshare this summer to get a view from the water.

Find out more about eagles and other birds on the first Saturday each month during our Early Birding hike with a naturalist. Or visit the Nature Center at North Mississippi (located at the east end of 49th Ave. N. along the river) to check out a seasonal activity backpack to use while exploring the park. Hike with a naturalist to look for signs of plant and animal activity at our Signs of Spring hike on Saturday, May 12 from 1-2 p.m. If you have young children, join the fun with our Nature Nuts playgroup for kids under six and an adult to explore the outdoors and learn about seasons, plants, and animals.

May Public Programs: May 5—Early Birding: search for birds while on a naturalist-guided hike, 9-10:30 am. May 12—Hike: Signs of Spring: Look for budding plants and other signs of the season, 1-2 p.m. May 19—Nature Art: Fairy Gardens: Build a miniature garden to attract fairies, $10, 1:30-3 p.m. May 27—Family Funday: Toads, Frogs, and Polliwogs: learn about our amphibian friends, 2-3:30 p.m.

Sign up kids ages 6-12 for Summer Day Camps, 8 a.m.-4 p.m. M-F $150 (full-day) or $80 (half-day) Camps run each week for the summer, starting June 11 (no camp July 4 week). Fee assistance is available – call for details.

Find registration and details for these programs and info at minneapolisparks.org or 612-370-4844. Do you have a question about nature in your own backyard? Then send it our way by emailing northmississippi@minneapolisparks.org and it could appear in a future article. This month look for frogs and toads! Create a drawing or take a picture and keep track of how many you’ve seen. Then show and tell a naturalist at the front desk to receive a North Mississippi Junior Naturalist button! Any images people would like to share will be displayed at the Center for the month of May. Like us on Facebook to stay in the loop about what is happening at your park!

Written by Victoria Thompson, Minneapolis Park & Recreation Board Naturalist at North Mississippi Regional Park