Things are really looking up for Wisconsin’s population of Bald eagle (Haliaeetus leucocephalus). In southeastern parts of the state, bald eagle populations were up 27% by the end of 2019, with other pockets of the birds also doing well.
Surveys compiled by the Department of Natural Resources (DNR) indicate that eagles occupied 1,684 nests in all but one Wisconsin county. In 2018, a record number of the species’ nests were located by the DNR, and a network of citizen scientists and bird enthusiasts. Bald eagles were considered endangered in Wisconsin back in the 1970s, with just 108 nests found at the decade’s low point. Today, the species is federally protected both by the Bald and Golden Eagle Protection Act, and the Migratory Bird Treaty Act.
“Bald eagles’ remarkable comeback continues as they expand into unoccupied territories,” said Laura Jaskiewicz, a DNR research scientist who’s coordinating the aerial surveys. “We’re also excited that many of the new nests were reported from the ground by landowners, raptor enthusiasts and volunteers, adding to the information we’re able to collect from the air.”
The bird’s nests are especially found in north western Wisconsin, which as the second-highest number of eagles nests in the state. Jaskiewicz says, however, that the region is reaching its carrying capacity for Bald eagles. Past years have also seen high numbers of nests in Vilas and Oneida counties. Most of the Northern Highland Ecological Landscape, representing 3.7 percent of the state’s total land area, is made up by these two counties.
Finding all the nests is a daunting task and the DNR encourages Wisconsinites to help. The birds actually start nesting around now, and may continue laying eggs as late as mid-February, according to a DNR press release. Eagle pairs mate for life, and normally choose the tops of large trees to build nests which are often reused annually. Amazingly, bald eagle nests can be anywhere from five feet to as large as 10 feet across, and weigh a ton or more. People who find new nests are encouraged to contact DNR staff like Jaskiewicz to report the discovery.
“There is definitely more public awareness of our eagle survey efforts, which no doubt is tied to an overall increased use of social media,” said Sharon Fandel, a DNR district ecologist with DNR’s Natural Heritage Conservation program, who is responsible for surveying southeastern Wisconsin. Increasing numbers of volunteers continue to assist programs like the Wisconsin Breeding Bird Atlas, and Bald Eagle’s Nest Watch, a program of the Madison Audubon Society.
“This volunteer project is providing valuable information on nest productivity in a highly urbanized landscape,” said Rich Staffen, the DNR conservation biologist who works with the group. “In 2019, we had challenges with making the low altitude flights in and around Madison. Fortunately, the volunteers were already monitoring the nests from the ground, so their information allowed us to provide a complete picture of eagle populations in the area.”