One of North and South America's most common bird of prey is also our smallest member of the falcon family. You have probably seen one perched along a road on telephone wires. There is one near our home that sometimes uses one of our feeder poles as a perch. The other birds take cover whenever the American Kestrel makes an appearance.
The American Kestrel is only about eleven inches long. The male's coloration is basically cinnamon on top and whitish below. The sides and back of his neck are yellowish-white with a spot of dusky-ash on each side of his neck. His wings are a fine bluish-ash. His head is marked with a unique black and white double-streaked pattern. His cere, feet, and the bare skin around his eyes are yellow. No other falcon has a rusty back and tail. The female's head and neck are streaked like her mates, but she has fine black streaks on her crown. Her back, shoulders, wings, rump and tail are cinnamon / rufous. Her tail is banded with 5 or 6 imperfect bars. Her chest and lower parts are pale yellowish-white with pale brown longitudinal streaks. Both sexes are very colorful and beautiful birds.
Behavior-wise, the kestrel is fascinating. Most often, it swoops down on its prey from a high perch, but when no perch is available, it can hover over the fields where it hunts. One of its more colorful common names is "windhover" which refers to its ability to remain nearly stationary for many minutes, suspended in the air by vibrating wings, while scanning the ground for grasshoppers and mice. Its other common name, "sparrow hawk" is somewhat of a misnomer. While the kestrel may dine on a few small birds up to the size of a quail, it is more likely to eat insects. It especially likes big grasshoppers, beetles or dragonflies. Voles, mice, bats, lizards, frogs, worms, spiders and crayfish are all on the menu. It can catch insects, bats and birds in flight.
Adult kestrels spend most of their time alone, even during the breeding season. In doing so, they employ a distinct division of labor in the raising of their young. The male remains on the hunting ground. He is solely responsible for feeding both himself and his mate. The female spends all of her time in the immediate vicinity of her nest. She does most of the incubating of the eggs. The male relieves her twice a day, once in the morning, and once in the late afternoon. Since it encompasses a few weeks before incubation, incubation, and the first few days of the nestlings' lives, this strict division of labor persists for up to twelve weeks.
Most kestrel displays occur in conjunction with "mate-feeding". While she is still perfectly capable of feeding herself, she begins to spend time on the male's feeding territory. The pair may hunt together. Soon, she stops hunting altogether, and relies upon her mate for all her food.
He approaches the nest with prey in his talons, accompanied by "whine call" (a loud, continuous sound, rising in inflection that may continue for up to two minutes) and rapid bursts of harsh chatter. His quickly fluttering outstretched wings are arched below his body. As he nears the nest, the female flies out and follows him while she performs the same movements and calls. He lands and she lands next to him. The bow repeatedly to each other. As she takes the food from him, they flutter their wings and chatter. Then she takes her food to one of her perches, and he returns to hunting. If she's not hungry, she stores it in the crotch of two branches for later. Usually, only parts of this complete ritualistic scenario are seen at any one time.
The two birds look for a nest site together. The male uses his fluttering glide, and harsh chatters to induce his mate to follow him. When she approaches, he flies off, carrying food, to a perch by an abandoned woodpecker or flicker hole in a saguaro cactus, a cavity in a snag, an old magpie nest, or even a hole in the bank of a stream. Kestrels will readily use manmade nest boxes, place 10 to 30 feet off the ground. Although eggs are not laid until Nay, a nest can be chosen as early as February.
From three to seven white or pinkish-white eggs, often marked with brown or lavender but sometimes plain, are laid from one to three days apart. Incubation starts just before the last egg is laid. As mentioned earlier, the female does most of the incubating. However, the male does enough incubating, about four hours a day, that he develops a brood patch of his own. While comings and goings from the nest are announced by whine or chitter calls, the birds are subdued during incubation and there is not much visible activity around the nest.
After thirty days, the young hatch out over a 3 to 4 day period. The female broods them constantly for the first few days, but by the 9th day, she only sits on them at night. The male brings all food for both his mate and young until they are no longer brooding during the day. By that time, the female has begun hunting again and takes on the majority of the feeding.
The nestling phase lasts for a month. While the parents do not carry the fecal sacs of their young away from the nest, the young do shoot their feces onto the upper walls of the nesting cavity where it dries quickly. Dermestid beetles live in the nest with them, and the beetles make a quick meal of any uneaten prey.
The young leave the nest over the course of a few days. For about two weeks they stay in the vicinity of the nest, making short flights. The female returns to the nesting cavity with them at night. The adults continue to feed the young, but are silent when they do so. The young, on the other hand, give a "whine call" and flutter their wings when their parents approach. They may even fly out to meet their parents on the wing.
The American kestrel is a common, but beautiful and intriguing falcon that lives in open or semi-open country just about anywhere it can find enough to eat. Its mate feeding is such a conspicuous display that if a pair is mating nearby, you should be able to watch it.