Reddish Vale Country Park
Kestrels defend only a small territory immediately around the nest. The larger home range where the birds find most of their food is often shared with neighbouring pairs. The home range is usually at least 1Km square, but can be as large as 10Km square.
When hunting, the Common Kestrel characteristically hovers about 10–20 m (c.30–70 ft) above the ground, searching for prey, either by flying into the wind or by soaring using ridge lift. Like most birds of prey, Common Kestrels have keen eyesight enabling them to spot small prey from a distance. Once prey is sighted, the bird makes a short, steep dive toward the target. It can often be found hunting along the sides of roads and motorways. This species is able to see near ultraviolet light, allowing the birds to detect the urine trails around rodent burrows as they shine in an ultraviolet colour in the sunlight. Another favourite (but less conspicuous) hunting technique is to perch a bit above the ground cover, surveying the area. When the birds spot prey animals moving by, they will pounce on them. They also prowl a patch of hunting ground in a ground-hugging flight, ambushing prey as they happen across it.
Common Kestrels eat almost exclusively mouse-sized mammals: typically voles, but also shrews and mice supply up to three-quarters or more of the biomass most individuals ingest. Other suitably sized vertebrates like bats, frogs and lizards are eaten only on rare occasions.
The female lays up to six eggs at two day intervals, and usually starts to incubate as she lays the third egg. The number of eggs produced depends on how much food there is, when vole numbers are low kestrels may not produce any eggs.
Incubation takes 27-29 days, the chicks need constant brooding for the first 10-14 days, after which the chicks can control their own body temerature.
The male provides the food for the female and chicks throughout the nesting period. The female will only hunt if food is in short supply, risking the loss of eggs or young chicks.
The chicks fledge gradually when they are around 4 weeks old. They explore increasing distances from the nest, but return to roost for another couple of weeks. The adults continue to feed the young for a month after fledging, during which time they will learn to catch their own food.
Kestrels are most easily distinguished by their typical hunting behaviour which is to hover at a height of around 10–20 metres (33–66 ft) over open country and swoop down on prey, usually small mammals, lizards or large insects. Other falcons are more adapted to active hunting on the wing. In addition, kestrels are notable for usually having much brown in their plumage.