We are grateful to Alan Williams for building and installing American kestrel (Falco sparvarius) nesting boxes for the EMJ and White House Farms. These gorgeous little hawks are also known as sparrow hawks.
By providing these boxes, it increases the birds’ ability to lay eggs (average four to six eggs per laying) if a suitable hollow tree or old nest can’t be located. Though the kestrel ranges over a large area including North America, Canada and Mexico, their numbers are declining in certain areas.
There are 17 recognized subspecies of kestrel based on vocalizations, plumage, size and range. There is a subspecies in the southeast US referred to as Falco sparverius paulus which has declined more than 80% since 1940 due to loss of habitat which decreases nest sites, mainly from the clearing of longleaf pines for agriculture.
The kestrel has striking markings with its light underbelly and rufous tail and back. It is the smallest raptor in America, being similar in size to a mourning dove.
They can be spotted around Page County, often perched on power lines or trees scouting for prey. While at rest on lines, they tend to bob their tails like they are trying to keep their balance. Because they are not particularly muscular like the merlin or peregrine falcon, they are not strong flyers so instead, tend to survey fields from vantage points for prey then ambush them as opposed to hunting while flying and expending a lot of energy. They will also practice ‘kiting’ or hovering over a field on rapidly beating wings and then diving for prey.
Because of being more aerodynamic and lighter in body, they do not have as high a caloric intake need. They eat small insects, dragonflies, grasshoppers, lizards, mice and voles and smaller birds. Like owls, they eject the indigestible parts of their meals in pellet form.
The kestrel is sexually dimorphic (male and female look different) with the female being larger. The female chooses a mate after the male dances for her and the pair form a strong bond, often permanent. The male brings her food when she has laid eggs and helps incubate the eggs.
Mr. Williams also built two barn owl boxes and installed these in the silos at the EMJ Farm on Long’s Road in Luray. A pair of owls had a nest under the roof eave of the historic home near the barn several years ago and the owls have been recently seen at the farm. We are hoping they will utilize the nest boxes in the silos and lay eggs which are safe from predators.
Barn owls (Tyto alba) are spectacular and have expressive white faces with heart-shaped markings and hunt at night on silent wings. They are medium sized but have long wings which makes them appear large if one is fortunate enough to see them in flight. Their flight is distinctive ‘buoyant, loping flight’.
During the day, they prefer quiet places to rest and will often take up residence in unused barns, silos, dense trees or sheltered cliff faces.
They hunt at night, utilizing their excellent eyesight and hearing to locate moles, voles, rabbits and other small mammals. The female regurgitates the indigestible fur and bones from these meals, shreds them with her feet and lines the next with the material to provide a soft bed for her clutch of eggs, generally anywhere from two to eighteen eggs at a time. The incubation time for the eggs is 29-34 days and the nesting behavior lasts from 50-55 days.
Barn owls tend to stay put and not migrate, particularly if they locate a nesting site they like.
One of the most distinctive qualities of the barn owl is their unusual calls – a series of hisses, clack and odd vocalizations that do not sound like the usual hoots of other owls.
We hope these boxes will soon be used by kestrels and owls – we will post an update if they are!
The Virginia Society for Ornithology is seeking landowners who are interested in placing American kestrel nesting boxes on their property. Click here for more information.