American Kestrel

 

Photo by: K. Leeker

Recently from the vantage point of the deck at Remington Nature Center my coworkers and me spotted a pair of American Kestrels as they dipped, dived and chased each other. We finally decided they were a pair beginning to show interest in mating. This prompted a discussion about putting up a nesting box to encourage them to stay in the area so we could continue to observe them. Kestrels typically use hollow trees, old nest cavities abandoned by other birds, on ledges of buildings and cliffs, but will also use manmade nesting boxes. 

Kestrels are North Americas largest falcon and are closely related to Peregrine Falcons. They typically hunt from a high vantage point, where they perch and watch the ground below for prey. They often bob their tail feathers up and down when they have spotted potential prey, before swooping down to capture their meal. They also utilize another way of capturing prey, as Ted Hughes wrote about in the following prose.

 “Effortlessly at height hangs his still eye. / His wings hold all creation in a weightless quiet/ Steady as a hallucination in the streaming air.”

This quote captures perfectly the American Kestrel ability to hover high in the air over open fields in search of prey. This ability to hover and glide earned them another common name of Windover. Their diet includes grasshoppers and other large insects, small rodents, lizards, and songbirds, which earned them another common name of sparrow hawk. Their population is estimated to be more than nine million individual birds, and 1.2 million breeding pairs. Their success can at least in part be attributed to their generalist diet. When you are willing to eat a wide variety of prey, their chance of growing their population and surviving habitat changes increases exponentially. Whereas birds that are specialists tend to struggle for survival when habitats are changed and their preferred food becomes scarce.

Photo by: K. Leeker

Many individuals have contacted me over the years upset about the “sparrow hawk” showing up at their bird feeders and capturing the songbirds they are so lovingly feeding. Humans tend to take ownership of something they are caring for, whether the animal is wild or domesticated seems to make no difference.

I view this situation as an opportunity to watch another amazing bird as it hunts and feeds. Yes, it can be upsetting to see songbirds killed before our eyes, but if we can take a minute to stop applying human emotion to something that is natural to these birds, we might be able to look at the kestrel as an interesting, instinct driven, bird of prey worthy of observing. When I am asked “what can I do to discourage the hawk” I recommend taking all bird feeders down for a week, to give the kestrel time to leave the area, and then try again. By leaving the feeders in place, and inviting songbirds to feast, you are also inviting birds of prey to feast on the very thing you are trying to attract. It is not just kestrels that will take advantage of this all-you-can-eat buffet, so will the Cooper’s Hawk.

Many years ago, while working for the Missouri Department of Conservation I noticed all the birds at the feeders outside my window take flight and disappear. I peered through the window and there was a Coopers Hawk perched with anticipation of capturing a meal at our feeders. I couldn’t help but chuckle at what must have been a frustrating situation for the hawk, to see so many options for a meal vanish in front of his eyes at his approach. After 30 minutes or so, he left, and the songbirds returned within 15 minutes. About 30 minutes later the same scenario played out and again there sat the Coopers Hawk. This action-packed situation went on for several hours before the hawk finally gave up. It was an amazing thing to observe.

Kestrels are approximately the size of a mourning dove, making them one of the smallest birds of prey in our region. They weigh between three to six ounces. This is equivalent to thirty-four pennies! Their lifespan is considered short for a hawk at fewer than five years in the wild. In captivity they may live more than ten years. Males are smaller than females and unlike most hawks and other birds of prey, they are dimorphic, meaning they look different from one another. Males have a blue gray head and back, both genders have hues of rust and white. Tails are barred and their faces have distinct, sharp lines.

Males arrive to breeding grounds ahead of females, and it is the female who will select her mate. They form strong bonds that often become permanent. They often reuse nesting sites from previous years. Usually, four to six eggs are laid, but occasionally they will lay as many as seven or as few as one. There is an indication that populations in some areas are declining. This is due to many factors, one of which is the removal of hollow trees and snags and using the cleared ground for grain farms and other human endeavors, which means nesting sites are not always readily available. We should strive to keep some of these small wild areas free from agricultural and other human activity. Encouraging these birds to live alongside us means free pest control. Rodents cause millions of dollars in damage, each year, to stored grain. They are also responsible for nearly 30% of structure fires, caused by their tendency to chew on wires. Kestrels work together to incubate the eggs and care for the young. Parents deliver two to three mice, or voles as well as other prey to the nestlings. If each chick is fed two to three mice every day, times four nestlings, times more than one million mated pairs in North America alone, you can begin to see the massive number of rodents that are being removed from the environment by kestrels alone, that isn’t factoring in all the other birds of prey also contributing to the reduction of rodent populations. That is a lot of small rodents!

If you are interested in learning more about kestrels or helping in the research of these amazing birds of prey: visit Peregrine Fund and check out the American Kestrel Partnership that was launched by them in 2012. This web-based network is for professional researchers as well as citizen scientists. They are asking individuals to monitor nest boxes and report their findings. This helps researchers to better understand the kestrel and its environmental needs.

These small predators are not only beautiful, and provide free pest control, they are also devoted partners and parents. The rodent control they provide is invaluable, and the enjoyment they provide just by watching their life play out before our eyes is enriching our own lives. Next time you are driving down a roadway, look at the wires and see if you can spot this tiny predator as he scans his habitat for a meal.