Lending a Helping Hand to Kestrels
We got hooked on kestrels after volunteering for a kestrel monitoring project with Audubon of Boulder County. These birds are found across the Americas and are the tiniest falcons around, about the same size as blue jays. They weigh just 3-5 ounces – that’s about the weight of 36 pennies! Some kestrels from Canada head south for winter, but plenty stay put year-round. They nest in woodpecker-carved holes, rocky nooks and even man-made structures. They primarily eat insects and small mammals, especially voles.
Kestrels are all about commitment – they’re monogamous and stick with the same partner and nesting area each year. They'll reuse nests, especially if their brood has thrived there before. Typically, females lay about five eggs, one every other day, and it takes a solid 28 days of incubation before they hatch. Once hatched, the chicks take another 28 days to fledge. If their first go at nesting doesn’t work out, they might try again later in the season.
Unlike bald eagles, peregrine falcons and other raptors whose populations bounced back after the banning of DDT, kestrel numbers have taken a nosedive – down about 50% since the 1970s. Loss of their favorite habitats might be a big reason why. They like hunting in open spots with short grass and perches to scope out prey. But as cities spread and farms shrink, these spots are getting harder to find.
Timing is key, too. Kestrels time their baby-making to match the period when prey is most plentiful. Their young have the best shot when eggs are laid just before spring. As the earth warms and spring arrives earlier, they might miss their window for raising a family if they can't adjust.
Luckily, there’s hope on the horizon. We can lend a hand by providing safe spots for nesting. Kestrels are happy to set up shop in man-made nest boxes, and bird-lovers across the country are stepping up to the plate. This spring, the Colorado Avian Research and Rehabilitation Institute put up 180 boxes statewide and Audubon of Boulder County rallied volunteers like us to keep an eye on local nests. Two mornings a week, we visit our assigned box, making note of what’s going on. So far, the female has been much more active, doing most of the hunting. Once the babies are two weeks old, the male will start helping with the feeding duties.