American Kestrel

a perplexing conservation mystery
Researchers have yet to find the definitive threats that are making this common species less common. As the global specialist for birds of prey, we've teamed up with researchers range-wide to help develop the big picture before it’s too late…


a male kestrel delivers a mouse to a female kestrel

Jim Shane

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American Kestrels are North America’s most plentiful falcon, hovering over agricultural fields, pastures, rural roadsides, and even suburban backyards and city skylines to hunt insects, rodents, and other small prey. This small falcon is familiar even to casual observers, but a look at population levels reveals a perplexing mystery: continent-wide, kestrels have declined by nearly half since the 1960s.

Recent research seems to indicate that rather than there being one singular cause of this decline, it is likely there are multiple causes. Kestrels in one part of North America may be reacting to threats differently than those in other parts of the continent, or facing different threats entirely. Some researchers are now focusing on the "where" and the "when" of kestrel decline rather than directly on the "why"—if we can determine at what part of the globe and at what age or time of year kestrels are most threatened, we can use that information to zero in on the causes. We're partnering with Boise State University to support breeding research here in Idaho, with the University of North Texas to study migration patterns and survival rates, and with other researchers range-wide to accomplish one singular goal: identify the causes of kestrel decline now and keep this common species common.

Threats to American Kestrels

Knowledge Gap
A smiling scientist removing a kestrel nestling from a nest box for banding

Matthew Danihel

our impact

Since 2015, we have partnered with a team of biologists and students from Boise State University (BSU) on Adopt-a-Box, a program that allows members of the public to symbolically adopt a kestrel box monitored by BSU scientists. Adopters receive a host of perks including updates on the kestrel families in their adopted boxes, while the funds raised pay for remote nest cameras and other equipment, replacement nest boxes, fuel for surveys, and more. It's a win-win!

Learn More and Adopt a Box
A kestrel perched on a utility wire with a purple leg band reading "6X" and two transmitter antenna on its back

Heather Bullock

our impact

For several years, we have partnered with a team from the University of North Texas to study kestrels at wintering hotspots in north and central Texas. By using GPS transmitters and field-readable alphanumeric leg bands, we're examining individual kestrels' movement patterns, how many survive each winter, and how many survive from one year to the next. These findings provide important clues about when and where kestrels may be in the most trouble.

A citizen scientist checks a nest box for activity during breeding season


our impact
From 2012–2023, our American Kestrel Partnership, a collective of approximately 2,500 professional and community scientists, contributed more than 60,000 observations from over 5,200 kestrel boxes and other nest cavities. These observations provide a detailed, decade-long snapshot of kestrel breeding activity range-wide and are getting us closer to understanding the slow, steady, and long-term decline of the American Kestrel. This program merged with Cornell Lab of Ornithology's NestWatch in February 2024; read more about this merger here.

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