Kestrel Project

In 2002, a Kestrel Nest Box Monitoring Program began at Beaver Creek Reserve. The nest box monitoring is done from March through July each year. As of 2009, 149 Kestrels had been banded. In the fall, the nest boxes are repaired and cleaned. Currently, there are 30 monitored nest boxes. These boxes are scattered along I-94, Eau Claire County and Chippewa County.

One or more banders licensed by the USGS Bird Banding Laboratory oversees the operation of each Kestrel nest box along the 125 mile route. The route is checked every two weeks, and takes approximately 7 hours. Adult Kestrels and juvenile Kestrels are banded. A truck is used to transport the equipment and extension ladders. Each nest box is checked by climbing ladders. Observers are welcome, and the likelihood of having an opportunity to see Kestrels up close is quite high, especially early in the morning. Processing birds must be done rapidly so it may not be possible to observe Kestrels for long. Anyone wishing to accompany the banders on the route, must make arrangements beforehand by calling the Reserve in advance. The Reserve will direct you to one of the Kestrel banders for further details.

American Kestrel Natural History

The American Kestrel is the smallest falcon in North America. This bird was formerly known as the “Sparrow Hawk”. American Kestrels are widely distributed across North America. Their breeding range extends from central and eastern Alaska across northern Canada to Nova Scotia, and south throughout North America, into central Mexico and the Caribbean. Most of the birds breeding in Canada and the northern United States migrate south in the winter, although some males stay as year-round residents.

The coloration of the feathers in Kestrels greatly varies between the sexes. Males have blue-gray secondary feathers on their wings, while the undersides are white with black barring. The back is rufous in coloration, with barring on the lower half. The belly and flanks are white with a black subterminal band on the tail. The back of the female Kestrel is rufous with dark brown barring. The wings exhibit similar coloration and patterning to the back. The undersides of the females are white with rufous streaking. The tail of the female is noticeably different from the male, being rufous in color with numerous narrow dark brown or black bars. In both sexes, the head is white with a bluish-gray top. There are also two narrow, vertical black facial markings on each side of the head; one below the eyes and one on the rear portion of the auriculars. Two black spots can be found on each side of the white orangish nape. Kestrels possess a pair of false eye spots on the nape of the neck. These dark circles are thought to be a form of protective coloration because they look like "watching-eyes" and may deter potential predators.

Juveniles exhibit coloration patterns similar to the adults.

Kestrels diet consists of insects, snakes, voles, mice, and sparrow-sized birds. Catching small birds requires a large energy investment, so they mainly dine on insects and small mammals.

Kestrels form pairs in which the bond is strong, tending toward permanence. Returning migrants commonly re-establish territories held the previous year. Kestrels commonly lay 4-5 white to reddish-brown spotted eggs. Incubation generally begins with the second to last egg laid and lasts about 30 days.

When the young are born, both parents tend them until they are ready to leave the nest at 28 to 30 days old. They continue to feed the young Kestrels two to three weeks after they leave the nest box.