As I drove down the main entrance road to Teller Refuge, I stopped to watch a small dove size bird hovering above the two-foot vegetation only to disappear in a quick dive to the surface below. Within seconds the bird lifted above the vegetation and flew to a nearby wooded post to consume its catch. The bird wasted no time tearing the small rodent into swallowing size pieces. Soon, several black-billed magpies flew in to harass this skillful predator, which you could detect, aggravated the bird that clung tightly to its prize. Within seconds it took flight clutching what remained of its earned meal and flew from its tormentors. The bird I was watching was the American kestrel. For years known as the sparrow hawk, this small raptor is actually the smallest North American member of the falcon family.
American kestrels are common throughout Montana and North America in general. They are one of the most handsome raptors with chestnut-colored back and head and striking gray and black facial plumage. Their wings tend to appear pale blue in the right light which contrasts beautifully with the dark patch spots on the back and chest. The males are slightly more colorful than the females. During the winter months in the Bitterroot, kestrels migrate to southern areas where food is more abundant. Yet, like clockwork, each spring when the valley warms up and insects begin to populate the fields, you can rest assured, the kestrels will be back.
Kestrels feed on a host of invertebrates such as grasshoppers, spiders, dragonflies, butterflies and beetles. They will feed on small vertebrates including voles, shrews and an occasional snake, frog or small bird. While they are in search of prey, as with most wildlife species, they have to keep a keen eye out for larger raptors that would delight in a fine kestrel meal. Sharp-shinned and Cooper’s hawks, as well as Red-tailed hawks, are common kestrel avian predators.
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One interesting fact that I learned about kestrels according to the Cornell Bird Lab of Ornithology, was that kestrels, like most birds, can see ultraviolet light that allows them to detect urine trails in the grass left by voles which are a common prey item. So, while I was watching the kestrel and admiring its skill in catching the small rodent, I did not realize that the rodent itself might have left a clear path to its capture.
From a conservation perspective, the North American Breeding Bird Survey shows a 50% decline in the species from 1966 to 2015. Speculation that improved “clean” farming techniques have reduced prey items, especially insects that are annually treated with crop insecticides. Other reasons such as tree removal in agricultural lands eliminate the nesting cavities from which the birds will nest and fledge their young. One positive management note is that kestrels will use artificial nesting boxes. They appear similar to the typical wood duck box with a smaller entry hole. The boxes must be maintained and monitored to reduce the occupation from Starlings. If chosen the female will lay about four eggs. When hatched, the chicks look nearly naked with some white feathers over their pinkish skin. If you have large cottonwood trees on your property, chances a natural nesting cavity already exists but don’t let that stop you from placing a nesting box. Next spring, you might be surprised to see a pair of kestrels raise a clutch there.
Sam Lawry, Teller Wildlife Refuge executive director has 35 plus years in the wildlife conservation profession. His contributions to the Ravalli Republic are intended to share some of that knowledge of wildlife in the Bitterroot with the community. If you would like more information about Teller Wildlife Refuge please visit our website at www.tellerwildlife.org.