Our American kestrels need more nests.

The numbers of North America’s smallest falcon have been in freefall since the 1960s and are now down by half due to loss of habitat, predation by Cooper’s hawks and other larger hawks, car strikes and eating poisoned prey, such as mice who’ve ingested d-CON pellets.

“With a population like this, that’s wildly declining, we have concerns about longevity of the species,” said Jennifer Redmond, a volunteer for the Estes Park nonprofit Colorado Avian Research and Rehabilitation Institute. “It’s important to be proactive instead of waiting until the species is endangered.”

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Not sure you’ve ever seen a kestrel in the wild? You probably have.

“They win the hearts of the public because they’re colorful, striking and charismatic,” said Redmond, who lives in Parker. “They’ll perch on telephone wires and bob their tail. They’re about the size of a robin or jay. Many think they’re a songbird.”

Kestrels, which eat insects, small mice and snakes and voles, are vital to the natural world. Having predators in the food chain helps increase biodiversity and contributes to the health of an ecosystem. Studies have found kestrels living next to agricultural land are a boon due to their voracious appetite for the aforementioned pests, which can wreck a crop. And farmers can rely on the diminutive falcons instead of chemicals to keep vermin at bay. But if there are no predators, like the kestrels, those pest populations will increase and upset the ecosystem’s balance, which could create problems for farmers and the food supply. We all lose if kestrels are extinguished.

To improve the bird’s numbers, CARRI has placed nest boxes throughout the Front Range for years. There are now 100 boxes from the Wyoming border south to Pueblo, though there’s a significant gap in boxes from Colorado Springs southward. Pueblo only has one.

The lack is due to not having enough participants in the community science project, says Redmond, who recently received an Aiken Audubon Foothills and Prairie Grant. She’ll use the funds to continue placing those boxes throughout the Pikes Peak region, along with gathering data and engaging with the community about the bird.

Kestrels are cavity nesters. They don’t build nests but will find abandoned woodpecker holes and lay their eggs.

“I’m partial to boxes because they’re made in a way that is predator resistant, with the depth of the box and overhang,” Redmond said.

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“So raccoons are not able to get in and reach the young. They’re built in a way that allows easy access and safety for birds.”

If people are interested, CARRI will place nest boxes on their property, though they’re not intended for regular backyards, unless the home backs up to an open space. Kestrels need a 2-mile range to hunt and preferably over open fields and ditches.

The boxes are important for two reasons. The loss of habitat means the birds need a safe place to raise their young. And having the boxes allows CARRI to help with research. Each one has a door on the side so workers can reach in and pull nestlings out for banding, which means putting a metal ID on one leg. It doesn’t disturb the birds and it doesn’t cause a parent to abandon the nest due to the lingering smell of a human, Redmond says.

The bands help researchers follow the birds. They can learn if the birds nest in another monitored box or, if someone gets a good enough photo of a banded bird in the wild, they can identify the bird and note how long it’s lived, how far it’s traveled, and how loyal they are to their nest site and mate, as kestrels tend to keep the same mate. That data is used by the Peregrine Fund’s American Kestrel Partnership. It is an international community science project that keeps tabs on how many eggs kestrels lay, if they successfully hatch and if the birds fledge.

“This is all information to solve the mystery of why numbers are declining,” Redmond said. “It’s a research project and conservation project at the same time.”

Contact the writer: 636-0270

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