Friday, March 16, 2012

Eagles!

Bald Eagle

(Transcript of today's For the Birds)

Right now we’re at the peak of eagle migration over Duluth. The crows in my neighborhood have been making a ruckus whenever eagles pass over, but they make a ruckus for everything else, too. This year’s eagle migration has been impressive, based on all the phone calls and emails I’ve been getting from people seeing them flying overhead. A lot of people are surprised to see them circling over parking lots, but when snow was covering the ground, roads and parking areas were the best places for thermal air currents to form. Now that the snow is melting again, thermals can form just about anywhere.

Bald Eagle

Frank Nicoletti and several other birders have been counting eagles along Skyline Parkway: the biggest days so far were March 11, when they counted 400 Bald Eagles, 21 Golden Eagles, and 16 Rough-legged Hawks, March 13, when they had 341 Bald Eagles, 5 Goldens, and 12 Rough-legs, and March 15, when they had 451 Bald Eagles, 28 Golden Eagles, and 12 Rough-legs. Other hawks are also coming through, though not in those numbers yet. The peak of migration for eagles usually falls sometime around March 25. Rough-legs and Red-tailed Hawks tend to peak in mid-April, and Broad-wings in early May, so there will be plenty of good hawk viewing in the coming weeks. (You can learn more about the count here.)

Many migrating eagles are headed to the far north. Eagles nesting in Florida and other Gulf Coast states started as early as late fall and many are already done for the year. Those nesting at our latitude started nesting in the past couple of weeks. Eagles reuse the same nest year after year, making some repairs in fall after their young are independent, and then making more repairs on the nest in spring before the first egg is laid. Eagle pairs usually mate for life, but we don’t know much about whether they spend the winter together except non-migratory pairs—at least some of them stay together all the time. Some mating behaviors are documented on wintering grounds, so some ornithologists believe that at least some eagle pairs may remain together year-round, but it would take long-term tracking of marked individuals to figure out for sure how often this happens.

Bald Eagle nest at Duluth East High School

Duluth East High School may be unique in the Lower 48 as a large public high school with an active Bald Eagle nest right on the school grounds, easily viewed from the parking lot or the athletic fields. The pair has returned there year after year since the school was a junior high school, and throughout construction when the building was rebuilt as a high school. I went on a bird walk around the school with some of Jenny Madole’s students on the Ides of March, and the highlight was seeing one of the eagles on the nest. The bird was sitting tight. She looked directly at us for a while, but I could also see her watching crows flying over, and also looking out in directions where I couldn’t see anything in particular, but she didn’t move the rest of her body at all. It takes about 35 days for the eggs to hatch, so students should be seeing fuzzy little heads peeking out in April, and the eaglets should be getting big enough to sit higher up by the end of the school year. It’s hard for the kids to be so near and yet not know for sure what’s going on inside that deep nest. Some students are investigating the possibility of getting a nest cam for next year—that would be a splendid learning opportunity for the entire community. Meanwhile, the kids are piecing together the eagles’ family life with glimpses of the birds as they can, while they plan out bird feeders and nest boxes to make East High School an even more extraordinary place of learning that will truly be for the birds.

Bald Eagle nest at Duluth East High School