American Kestrel Monitoring 2023

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2023 was another record breaking year for Madison Audubon’s (MA) American Kestrel Nest Box Monitoring program. With 228 kestrel boxes spread over 12 counties, these small, but fierce, falcons had plenty of cavities to choose from despite diminishing natural cavities across our focus area in southern Wisconsin. These kestrel boxes not only provide a safe place to lay their eggs and raise their young, but they also allow easy and reliable access to the watchful eyes of over 100 devoted volunteer monitors. 

2023 data table. Boxes occupied: 78/228. Occupation rate: 34%. Successful occupied boxes: 67. Nest success: 86%. # eggs: 377. Average # eggs per nest: 4.8. Brood size at banding: 4.3. unhatched eggs: 75. Estimate # fledged: 294.

Kestrel Nest Box program data from 2023.

With the help of our volunteer nest box monitors, we are able to gain vital information about the lives of these declining raptors. In 2023, kestrels occupied 34% of our boxes (78 out of 228). Of those 78 boxes, 67 successfully raised young. We found that the average clutch size was 4.8 eggs, and that 80% of the eggs hatched. In total, we estimate that 294 young kestrels hit the skies around southern Wisconsin thanks to MA kestrel boxes. 

Beyond providing vital kestrel nesting habitat, the MA Kestrel Nest Box program provides invaluable data to the Peregrine Fund’s American Kestrel Partnership (AKP). MA has been one of the largest contributors to the AKP’s database since their inception in 2012. In 2022, our monitors submitted a record-breaking 1,725 nest box observations to the AKP, and were featured in the AKP’s Fall 2022 Newsletter. However, Goose Pond Sanctuary land managers Mark Martin and Sue Foote-Martin began erecting and monitoring kestrel boxes in the mid-1980s. Thanks to Brand Smith, monitoring coordinator for the MA kestrel program who joined in the mid-2000s, our kestrel program expanded tremendously in geographic range, volunteer involvement, data collected, and nest boxes available. I have no doubt that MA will continue to be one of the top organizations to submit data to the AKP as our program continues to grow. 

Graph showing increasing number of kestrel fledglings per year since 2012.

As the MA kestrel project grew from 34 available boxes in 2012 to 228 boxes in 2023, the number of kestrels fledged from our boxes increased from 8 in 2012 to 294 in 2023.

2023 was also a record year for our banding efforts. In 2016, Janet and Amber Eschenbauch from Central Wisconsin Kestrel Research began banding adult and nestling kestrels in the boxes around Goose Pond Sanctuary to supplement their research at the Buena Vista Grasslands, as well as to educate MA members and volunteers about this fascinating little raptor. 

In the last few years, we have dramatically expanded our banding efforts with the help of Master bander, Kurt Reed. Under Kurt, Brand Smith and myself (Emma Raasch) have been sub-permitted to band American Kestrels. This year, we were able to band adults and nestlings at every active box for a total of 356 newly banded kestrels! Out of the 59 adults captured, 21 had been previously banded. By recapturing adults, we are able to learn more about their age, nest-site fidelity, and more.

Kestrel banding success each year since 2016.

For example, after banding the first two adults of the year, I asked Brand if kestrels breed during their second year. This seemed like a simple enough question, but still, we were uncertain of the answer. A quick Google search revealed that while it’s biologically possible for kestrels to breed during their second year, they are often out-competed for nesting cavities by older birds. 

The next banding excursion was at a box in Jefferson, WI. Upon looking at the captured adult female, we noticed she was banded, but not with a number that we recognized. Kurt submitted the band number to the Bird Banding Laboratory (BBL) and discovered that that female was banded as a hatchling on June 21, 2022 at the Sauer Prairie Kame Forest Preserve near Kaneville, IL. This meant that that particular bird traveled approximately 84 miles north of where it hatched to nest, and that it successfully nested in its second year! I later learned that a young male kestrel that Janet and Amber banded in one of our MA boxes nested in one of their boxes, 90 miles north, the following year.

Emma, wearing a plaid shirt and hat, reaches up to a wooden nest box to put a young kestrel back inside. The background is a leafy green tree

Emma carefully returns a banded kestrel to its nest box (photo by Robert Rolley).

I’m very grateful to have had the opportunity and privilege to work with these birds so closely this year. What stuck out to me the most was the range in personalities and dispositions of both adults and nestlings. While approaching their nest boxes, some birds would require CIA level stealth to reach their box without flushing them. For others, I could trip on the way to the box, and they would still hang tight on their eggs. Likewise, some chicks would sit calm and obediently, while others would squirm and bite my fingers throughout the whole banding process. Whether it was adults or chicks, when I opened the box, I never knew what I was going to get!

With nest monitoring and banding behind us, it may seem like we’re “done” with kestrels for the year. However, Brand Smith and volunteers are still busy as ever putting up new boxes and moving unsuccessful boxes to new locations. And lucky for us, American Kestrels can be seen in Wisconsin at all times of the year. Even when our breeding birds and fledglings head south for the winter, we can still rely on these flashy falcons to brighten our days as they perch on power lines.

A volunteer holds a very vocal young kestrel just prior to the bird being banded (photo by Robert Rolley).

I’d like to sincerely thank everyone who helps make the MA kestrel program a tremendous success! It takes a village to do citizen science at this scale, and every single monitor, ladder holder, and note taker, makes what we do possible. Thank you so much to Kurt Reed for providing his training and banding expertise to myself and Brand. We’d also like to give a special thanks to Janet and Amber Eschenbauch for sharing their banding experience and passion for kestrels with all of us at MA. Last, but certainly not least, I’d like to give a HUGE thanks to Brand Smith on behalf of every volunteer, collaborator, MA staff member, and even American Kestrels themselves! The MA Kestrel Nest Box program would not be what it is today without Brand’s infectious passion and dedication for these birds. Thank you for keeping us all on track! 

And, a volunteer testimonial:

I wanted to send a thank you note for such a wonderful program. We enjoyed the experience this year and will certainly keep participating. My kids are hooked on kestrels! They have even begun to play “pet vet” where they take care of kestrels and nurse them back to health! They even managed to spot a few around our homes for a few weeks this summer. Thanks again for a wonderful program, we will certainly continue to participate. Let us know if there is anything else you or the program needs assistance with. Thank you!

Written by Emma Raasch, Goose Pond Sanctuary Ecological Restoration Technician
Cover image by Robert Rolley. Two American Kestrel young are held in hand just prior to being banded.

**All banding, marking, and sampling is being conducted under a federally authorized Bird Banding Permit issued by the U.S. Geological Survey’s Bird Banding Lab.