Assisting the American Kestrel
(This 893rd Buffalo Sunday News column was first published on May 4, 2008.)
Iain MacLeod with a kestrel nestbox
Recently Peter Ciotta contacted me to tell me how Solar, a Jacksonville, Mississippi subsidiary of Buffalo's Gibraltar Industries, is contributing 100 rural mailboxes to be converted to provide nesting sites for kestrels, another of those species whose population is in serious decline. Their contribution supports a project of New Hampshire's Squam Lakes Natural Science Center.
Male and female kestrels. Painting by Louis Agassiz Fuertes
When I was a youngster, this raptor was called a sparrow hawk. But then the remarkable Roger Tory Peterson, who revolutionized birding in the 1940s with his first field guide, assigned to it the name of its European cousin and the sparrow hawk became the American kestrel. (At the same time he renamed the sparrow hawk Peterson changed the name of pigeon hawk to merlin and duck hawk to peregrine falcon, thus in all three cases giving these falcons names that avoided their less attractive side at a time when hawks were too often shot as vermin.)
The American kestrel is indeed a tiny hawk. At nine inches in length, it is even smaller than a robin's ten inches. I most often see kestrels perched on telephone lines where I find it easy to mistake them for mourning doves. This is due to their posture and shape because the doves are nearly twice their size.
Observed in this way only in silhouette the kestrel's beauty is missed. Both males and females are very attractive when seen in good light. Both have bright rufous backs and tails and what David Sibley calls "boldly patterned heads." Vertical grey lines on each side of their eyes give them a helmeted appearance, somewhat like that of the peregrine falcon. The rufous coloration of the back is carried over to the wings of the female, but the male's wings are grey. The female's throat, breast and stomach are also rufous streaked on white while the male's white underparts are only lightly spotted with grey.
It is interesting to watch kestrels hovering thirty to forty feet high over an open field looking for prey in the grass below. In spring when they depart from their usual solitary habits to mate, the pair often communicate with each other with high-pitched screams of killy-killy-killy or klee-klee-klee that are similar to the killdee calls of the killdeer. (I once embarrassed myself by pointing out a killdeer to Harold Axtell that he gently informed me was a kestrel. My only excuse: the killdeer also has an orange lower back which I took for the kestrel's rufous.)
All falcons are designed for fast flight. Unlike the sharp-shinned and Cooper's hawks, their wings are sharply pointed and, except when they hover, the falcons dash about in a great hurry while those accipiters usually flap and glide.
But the kestrel is still a carnivore. With that former name in mind we should consider its food. In summer most of its diet is grasshoppers, dragonflies, lizards, mice and voles. But in winter, while they continue to feed on small mammals, they also take birds, indeed mostly sparrows.
Maryland birders Richard and Diane Van Vleck even set out mice during three periods of stress for their local kestrels: when they have young, when local fields are sprayed with pesticides and during severe winter storms.
My own observations suggest that these tiny falcons are far less common today than when I was a youngster and counts at migration stations confirm this. They indicate that the kestrel population has declined by more than half over the past 40 years.
Thus kestrels do need our help and I recommend that country dwellers put out nest boxes. Kestrels are cavity nesters and take well to such boxes. You too could convert one of those metal mailboxes to this purpose, but wooden boxes also serve. In "Your Backyard Wildlife Garden" Marcus Schneck recommends an 11" by 11" base by 12" high box with a 3" by 4" hole. Mount the box 20-30 feet above the ground in an open area.
One such nest box is mounted behind the administration building at Iroquois National Wildlife Refuge. A camera in its top records the lives of the kestrel family and plays them inside the building.
I salute Gibraltar for its contribution to the welfare of this threatened species.-- Gerry Rising