The American Kestrel is the smallest falcon species in North America, known for its adaptability and wide distribution across diverse landscapes, from open grasslands to suburban parks. As a diurnal predator, the kestrel hunts exclusively during the day, relying on sharp eyesight and swift movements. Its flexible diet and dynamic hunting strategies allow it to thrive in varied environments.
Primary Food Sources
The diet of the American Kestrel is notably broad, relying heavily on invertebrates, which often constitute the largest percentage of its food intake. Large insects are the most significant component, especially during the breeding season when energy demands are high for feeding young. Favored arthropods include grasshoppers, crickets, beetles, and dragonflies, which are abundant and relatively easy to capture in open habitats.
Small vertebrates are an important secondary food source. Small mammals such as voles, shrews, and mice provide concentrated energy and fat, especially in colder months when insects are scarce. Kestrels also prey on small birds, including sparrows and finches, though these are taken less frequently than mammals.
The kestrel is opportunistic and consumes other available prey when conditions allow. In specific habitats, small reptiles like lizards and snakes are captured and eaten. Amphibians such as frogs may also be taken, especially near water sources or during wet periods.
Hunting Techniques and Feeding Behavior
The American Kestrel employs several strategies to acquire prey, the most common being perch hunting. This sit-and-wait approach involves scanning the ground from a high vantage point, such as a utility wire or tree branch. Once prey is spotted, the kestrel executes a rapid dive, or stoop, plunging down to capture the meal with its talons.
The kestrel’s unique hovering technique, sometimes referred to as kiting, is another method. The bird uses rapid wing beats to remain stationary in mid-air over an open field, keeping its head still while scanning the vegetation below. This strategy is primarily used in open areas that lack suitable perches, allowing the falcon to maintain a predatory vantage point before striking. Kestrels also demonstrate aerial agility by catching insects and sometimes small birds directly in flight.
Upon capture, small insects are often consumed whole, sometimes even in the air, but larger prey requires specialized handling. The kestrel uses its sharp talons to secure the prey, and then delivers a killing bite to the back of the head. This bite is administered using the tomial tooth, a sharp, notched projection on the upper beak common to falcons. If a kestrel catches more food than it can immediately consume, it will cache, or store, the excess food in a safe location for later retrieval.
Seasonal and Geographic Shifts in Diet
The kestrel’s diet changes significantly in response to seasonal fluctuations in prey populations. During the summer breeding season, the diet is heavily weighted toward abundant insects and other arthropods. This insect-heavy diet is important for feeding growing nestlings, requiring parents to deliver a high volume of food.
As seasons transition to winter, the diet shifts as insects die off or become inactive. Falcons pivot to a more energy-dense menu composed of small mammals and birds. This change provides the caloric intake needed to survive colder temperatures and reduced daylight. Migratory kestrels follow their food sources, moving south from northern latitudes to regions where prey is consistently available.
The immediate habitat also dictates the kestrel’s specific prey choices. Kestrels hunting in open grasslands may rely heavily on grasshoppers and voles. Conversely, those living in urban or suburban environments incorporate more house mice or small birds that frequent backyard feeders. This ability to utilize locally dominant resources allows the American Kestrel to maintain its wide distribution.