Birds of the Hackensack: 

American Kestrel

 

By Ivan Kossak

 

Although it is the smallest North American falcon, the American kestrel (Falco sparverius) is still visually impressive, whether it is swiftly flying in search of prey or perched on a thin branch or telephone wire.  An adult male American kestrel shows a striking plumage pattern with its reddish-brown back and tail sharply contrasting with its blue-gray wings and crown. The kestrel’s cheeks and throat are white with two black stripes running down the neck from the crown giving the appearance of a drooping mustache and sideburns. The male’s breast has a light brown wash to it while its lower breast and belly are speckled with dark spots. Female kestrels look quite similar to the males although they lack the contrasting wing colors and maintain the same reddish brown throughout their upperparts. The speckling on their underparts is also a reddish brown. Only nine to 10 inches long, kestrels are delicately built, their wings appearing rather pointy in flight. Their diet consists mostly of insects, small reptiles and occasionally small birds. In late summer, I have seen migrating kestrels congregate on, of all places, a ski lift – diving into the tall grass below to feast on crickets and grasshoppers. 

Kestrels are cavity nesters. That means they need either trees that are mature enough to have developed hollows and woodpecker holes, or man-made structures such as barns in which to build their nests. Once a suitable nesting location has been found, the female kestrel will lay three to five eggs that will take about a month to hatch. It will typically take the young another month to fledge and begin to hunt on their own. Because the incubation and rearing period is so long, kestrels usually do not migrate great distances between nesting and wintering areas.

American kestrels breed throughout virtually all of North America and winter from the Great Lakes south into Mexico. They can be seen in migration flying north (mostly late March through early May) to breed and then south (mostly in September and early October) to their wintering grounds. Kestrels are birds of open country and have been a familiar fixture in farmland throughout North America. However, as a result of the development of a great deal of New Jersey’s farmland into suburban housing tracts and office parks, the Garden State’s population of kestrels has shown a marked decline in recent years. Now, they rarely nest in the eastern part of the state and migrant numbers have decreased as well. The grassy portions of the Meadowlands provide some of the best habitat for kestrels to nest in northeast New Jersey. However, because of their small size, the American kestrel must be careful in the Meadowlands or this diminutive predator may become prey itself for its larger and more powerful cousin, the Peregrine falcon. You may spy a migrating kestrel in such places as Overpeck Park or Kearny Marsh where their food is abundant.