Two Bald Eagle nestlings and adult. Photo by Amber Leifheit, BENW volunteer
Last month, Bald Eagle Nest Watch (BENW) volunteers submitted their final reports for the year. The eaglets have fledged! It is a bittersweet time, as the eagle families that our volunteers have been monitoring since February have successfully completed their nesting season.
The fuzzy little eaglets are now full-sized, dark brown gliders in the sky. The majestic and imposing parents that were recently charged with gently tending delicate eggs and chicks are now tasked with teaching their newly flying young to feed and protect themselves.
It’s a shift in the seasons and a fun one, at that. We’re excited to share that this was a very successful year for Bald Eagles. In 2023, over 400 volunteers documented 219 new eaglets from 208 nests in 39 Wisconsin counties took to the skies!
Fledgling in the sky. Photo by David Stank, former BENW volunteer
How the program works
In January each year, volunteers sign up, receive training, sign a confidentiality agreement, and are assigned to a nest in their area. Starting in 2021, Madison Audubon began partnering with other organizations to bring the program to their areas, so those organizations are involved in the training and volunteer coordination (see below for partner information).
When volunteers visit the nest, for an hour each week, they stay back 300 feet or more to avoid disturbing the eagle family. No one can see into the nest, so everyone watches the adults’ body language until the chicks are big enough to be seen over the edge of the nest.
Volunteers documenting if they see nest building, incubation, brooding, chicks growing, feeding, flapping, branching, and eventually, fledging. They submit their observations to our data portal, which dumps into a central database. The database is monitored and managed by Madison Audubon and shared with the Wisconsin Department of Natural Resources at the end of the season.
As a result, the program is able to monitor productivity of nests and if something goes wrong at the nest, we can have an idea of why.
This year’s end of the season report can be found here.
Data for each of the six program areas are as follows:
Central WI — 14 nests watched in 3 counties, 12 fledglings, 20 volunteers. Coordinated by Nature’s Guide Independent Naturalist Service
Door County — 7 nests watched, 3 fledglings, 15 volunteers. Coordinated by The Ridges Sanctuary
Eau Claire — 16 nests watched in 4 counties, 11 fledglings, 32 volunteers. Coordinated by Beaver Creek Reserve
Fox Valley — 39 nests watched in 6 counties, 35 fledglings, 90 volunteers. Coordinated by 1000 Islands Environmental Center
Manitowoc County — 8 nests watched, 6 fledglings, 13 volunteers. Coordinated by Woodland Dunes Nature Center
Southeastern WI — 15 nests watched in 4 counties, 21 fledglings(including 3 in Milwaukee County for the first time in at least 120 years!), 32 volunteers. Coordinated by independent volunteer
Southern WI — 101 nests watched in 18 counties, 120 fledglings, 235 volunteers. Coordinated by Madison Audubon
We had about an 86% success rate at the nests which is slightly higher than the average year.
So. Many. Stories!
The season’s overall data and statistics are wonderful and worth knowing. But the stories from the season are just as interesting. Here are just a couple of examples.
This spring, volunteers at a Dane County nest documented the older of two chicks feeding the younger one, which is a rare and unusual behavior. While normally chicks compete over food, volunteer Jill Falkosky described the situation as “calm, non aggressive, no tugging… it was like a parent feeding a young.” Photos of one of the feedings is below, taken by volunteer, Terri Bleck. A truly amazing observation that is made possible by volunteers spending a lot of time at the nest!
Photos of a chick feeding a sibling by Terri Bleck, BENW volunteer
Another story comes from Walworth County, where volunteer Frank Cahill watched an eaglet grow big and strong and suddenly spotted another—much younger—eaglet in the nest. What a shock!
There is no clear explanation for this age discrepancy of almost 2 weeks apart, we have never heard of it before! Were they from the same clutch of eggs? Did the female lay another egg later on for some reason? We will likely never know.
Two eaglets in the same nest, about two weeks apart in age. A highly unusual sight! Photo by Staci Otradovec, community member not affiliated with BENW
Let’s turn to Milwaukee County, where the first fledgling in over 120 years was documented. And not only was there one, there were THREE — from two nests! This is huge. In 2022, BENW volunteers documented the first active Bald Eagle nest in Milwaukee County in many decades (though the nestling died, likely due to avian flu — more below). This year, two nests were active and both produced young.
“I never thought I'd see a Bald Eagle in Milwaukee County in my lifetime,” said Robin Langenbach, BENW volunteer who monitors the nest where the first fledgling hatched. “Now we have our first fledgling! It's a testament to how conservation and citizen science programs like Bald Eagle Nest Watch can have such positive results.”
WOW. So great!
The first fledgling documented in Milwaukee County in over 120 years! Photo by Ken Martin, BENW volunteer
And each season, there are situations in which our volunteers sound the alarm and a rescue or intervention is in order. Whether it’s eaglets falling out of the nest, adults found with lead poisoning, or disturbances in the area (like nearby tree cutting), BENW are great advocates and educators that work with the appropriate respect and resources needed to help the eagles. It’s a privilege to be part of that inspiring and forward-thinking community!
In 2022, the leading story was centered around the Highly Pathogenic Avian Influenza (HPAI). The disease spread through wild and domesticated birds like wildfire and resulted in a major disruption in populations. Because BENW volunteers were in the field documenting nesting behaviors and results, the program was able to capture the dramatic decline in nesting success as a result of HPAI—only 35% of the nests successfully produced young (in typical years, that number is closer to 85%). It was a sad and difficult year, but it provided an invaluable data point to understand the toll that the disease took on Bald Eagles. Thankfully, the Bald Eagle population is strong enough in Wisconsin to weather a poor nesting year, and in 2023 the nest success rate was back to its normal 86%.
From humble beginnings
The Bald Eagle Nest Watch program began in 2018 after Drew Cashman came to Madison Audubon with the idea of creating a program in Wisconsin that documents Bald Eagle nest activity and shares that information with the WDNR. The goal: to better understand how Wisconsin’s eagle population is doing. The BENW program is modeled after a similar program in New York and Colorado.
Drew Cashman (blue and black coat in center) at the first BENW training in January 2018 with the first group of BENW volunteers. Photo by Brenna Marsicek / Madison Audubon
That first year (2018), the program had 43 volunteers monitoring 14 nests, primarily in Dane County. Since then, the program has grown—approximately doubling in size each year—thanks to the continuously increasing number of volunteers and partners:
In 2021, we launched a branch in the Fox Valley in partnership with 1000 Islands Environmental Center, and began working with a group of volunteers already watching Bald Eagle nests in southeastern Wisconsin.
In 2022, a Central Wisconsin branch was formed, coordinated by Nature’s Guide Independent Naturalist Service.
In 2023, three new branches formed: The Ridges Sanctuary coordinates volunteers in Door County; Woodland Dunes Nature Center coordinates the program in Manitowoc county; and Beaver Creek Reserve leads the charge in the Eau Claire and Chippewa Falls area of Wisconsin.
A map showing which counties in 2023 have at least one nest being monitored by BENW volunteers.
With all of these efforts combined, we are able to monitor nests in over half of Wisconsin’s counties, and we welcome folks to join in the fun and meaningful work next year! Keep an eye on the website (madisonaudubon.org/benw) in December for a public sign up to participate.
Thank you to our volunteers, partners, private property owner partners, public property owner managers, and the wildlife rehabilitation centers that help the eagles our volunteers bring in. This work could not be done without you!
Written by Brenna Marsicek, Madison Audubon director of communications and outreach and BENW statewide co-organizer
