Pygmy owls: small but fierce predators

Tiny raptor has eyes in the back of its head

Because most of their activities are nocturnal, owls are more often heard than seen and often are regarded as mysterious and secretive. There's certainly something thrilling and primordial about hearing an owl call in the darkness of the forest.

After spending almost two years at Walden Pond, Thoreau described that experience this way: "For sounds in winter nights, and often in winter days, I heard the forlorn but melodious note of a hooting owl indefinitely far; such a sound as the frozen earth would yield if struck with a suitable plectrum, the very lingua vernacula of Walden Wood, and quite familiar to me at last, though I never saw the bird while it was making it."

According to the Owl Research Institute at Ninepipe, there are 20 breeding species of owls in the United States and Canada. These owls are divided into two groups: Tytoninai (barn and bay owls) who are easily identified by their heart-shaped faces and Strigidae (all other owls) who have round faces.

All owls have developed several interesting physical adaptations to help them cope with their nocturnal and solitary lifestyle.

First, all owls have large heads to accommodate their large eyes and ears. Owls also cannot move their eyes up and down or side to side as humans do, so to compensate they have evolved the ability to rotate their heads approximately 270 degrees. In some species the ears are asymmetrical, with the right ear longer and located higher on the skull, allowing calculation of flight angles when sounds are heard but the prey cannot be seen.

Owl feathers in many species are structured so that flight sound is absorbed. Consequently, these owls cannot be heard by potential prey as they approach. Since most owls take prey items from the ground or from trees and shrubbery, they have powerful feet with outer toes that can rotate so that two toes point forward and two backward. This adaptation permits a strong symmetrical grip on squirming prey.

Once prey is captured, owls avoid interaction and competition for this food by gulping the prey down whole rather than eating in the open as hawks are more likely to do. This rather gluttonous behavior is possible because the digestive system compacts the indigestible materials such as fur and bones into a pellet and one or two of these pellets are ejected through the mouth daily. Owl researchers rely on these pellets to help locate roost sites and scientists also can determine the diet of owls from study of the contents of these pellets.

One of the most commonly seen owls in the Flathead is the northern pygmy, the only small diurnal (active chiefly in the daytime) owl in this area. If you regularly feed birds in your yard, the chances are quite good that you'll have one at your feeders - not to check out your sunflower seeds but to check out and dine on the other birds that are there.

In addition to small birds, the northern pygmy owls' diet consist of mammals, insects and probably a few reptiles and amphibians. Small birds may be an important part of its diet especially in the winter when some of the other food sources are limited. Because of this, the northern pygmy is a favorite target of songbirds and can sometimes be located by watching or hearing a group of small birds cry in alarm and mob the owl.

Despite its petite size (approximately 7 inches and 2 to 3 ounces) the northern pygmy owl is a fierce predator and has been known to attack and kill prey much larger than itself. The northern pygmy has a round head and yellow eyes and bill.

Its eyebrows are a distinctive white and feathers extending from the back of the eyebrows can be raised (like tufts) when alarmed. A true facial disk is absent. The head is finely spotted and the dark mottled head and neck give way to a white chest, belly and sides, with vertical brown streaking. The tail is conspicuously long with dark barring. For protection, the northern pygmy owl has a special protective adaptation that most parents and teachers have often wished for - eyes (actually false eyes) in the back of its head.

Northern pygmy owls begin breeding in April and during this time their call is a repetitive "toot" pause "toot." Listening for this call in the evening, night and early morning is a good way to locate these small owls and if one happens to locate near your bedroom window it will be hard to miss.

Denver Holt of the Owl Institute reports that he's had more than a few calls from frustrated homeowners who would just like those pesky owls to go away so they can get some sleep. Most owls are monogamous with many keeping the same partner until one dies.

Not much is known about the sexual displays of owls but because they happen primarily at night.

Northern pygmy owls nest in old woodpecker holes where they lay three to five eggs that are incubated for approximately 25 days. During breeding and incubation the male delivers food to the nest, but as the young become larger and the food demands become greater the female joins in the foraging. Fledging occurs in four to five weeks but the young remain with their parents for another four to five weeks. Most North American owls raise only one brood per year.

Energy demands made by the late summer molt make raising a second brood impractical since hunting for food for the female and the young would be very difficult for the males while they are replacing their wing and tail feathers.

Take time soon to go for an evening walk and listen for the plaintive call of a lonely male owl looking for a mate. The sound will be one you won't soon forget. Remember spring is just around the corner and springtime in the Flathead Valley offers many fantastic birding opportunities.

To learn more about the northern pygmy or any of the other owls in this area visit the Web site of the Owl Research Institute at www.owlinstitute.org/index.html.

The Institute offers many interesting tours and programs and founder and wildlife researcher Denver Holt has received worldwide recognition for his work.