The American kestrel (Falco sparverius) is a small falcon found in North and South America. Often referred to as the sparrow hawk, American kestrels are the smallest falcons in the Americas, as well as the only kestrel. They are also extremely numerous, with an estimated 4 million living on the two continents. American kestrels are 7-8 inches in length, and have a wingspan of less than two feet, making them very small for a bird of prey. Females tend to be larger than males, and lack the blue-grey coloring found on the male’s wings and head.
American kestrels can be found from subarctic Canada all the way south to the tip of Tierra del Fuego. They prefer to live in open areas with plenty of available perches such as trees, fence posts, and power lines. This allows them to see and pounce on small prey such as grasshoppers and mice. However, when adequate hunting perches are not available, the American kestrel is capable of hovering in one place using very rapid wing beats, not unlike a hummingbird.
Most American kestrels migrate south each winter, but depending on local weather conditions, they may become full-time residents. Regardless, in the winter most female kestrels will stay in open country with better hunting available, and force the smaller males into deeper woods. Kestrels prefer to nest in cavities in trees, and they will occasionally nest in holes carved out by large woodpeckers. Their desire for covered nests and open hunting ground has led them to naturally adapt to urban and suburban environments, and they nest frequently in building alcoves.
Each spring, kestrels return to their breeding grounds. The males arrive first, followed by the females, who will select a mate. Once mated, the two will likely remain together permanently, and use the same nest for breeding each spring. The female will lay three to seven eggs, which will require 1 month of incubation, a responsibility both parents share. Once the baby kestrels are born, they grow very quickly, and will reach adult weight in less than 3 weeks. They are able to leave the nest after less than one month. Although captive kestrels (which are often used for falconry) can live upwards of 10 years, most wild American kestrels live a scant 15 months, with car strikes being a frequent cause of death in populated areas.
AMERICAN KESTREL FACTS
- American kestrels are protected by the Migratory Bird Treaty Act of 1918, and are illegal to possess without a permit.
- American kestrels have been seen living at an elevation of 14,764 feet in the Andes Mountains.
The Cornell Lab of Ornithology
Field Guide to Birds of North America