Nature talks: Northern Saw-whet Owl

What’s 7 inches tall and weighs about the same as a stick of butter? Actually, a stick of butter weighs more. The answer is a Northern Saw-whet owl.

The saw-whet is brown with a white, red-brown streaked belly. Their large yellow eyes are topped by a V-shaped white patch and surrounded by a white facial disc that blends into the brown and white speckled crown. One of the most common owls in forests across northern North America (and across the U.S. in winter), saw-whets are very seldom seen. Their high-pitched too-too-too call is a common evening sound in our forests from January through May. Like most owls, saw-whet owls are nocturnal and tend to be most active just after dusk and near dawn.

This owl (Aegolius acadicus) is a year-round resident of Pennsylvania and an overwintering migrant species of states to our east, west, and south. Its unusual name is derived from the sound of its calls. These calls have been variously described as resembling the sound of water dripping into a half-filled pail or the pinging that is generated when a saw blade is being sharpened (or “whetted”). The northern saw-whet vocalizes only during its breeding season (March to May) and uses its song both to attract mates and to mark its breeding territory.

Despite its size the saw-whet is a predator preying upon deer mice, shrews, voles, beetles, grasshoppers, moths and bugs. The saw-whet has excellent vision and hearing to locate prey.

During cold weather, the saw-whet may cache extra kills in tree holes where they can remain frozen and preserved for many months. Before consuming these cached food items, the owl will warm them with its body (almost like incubating eggs).

Nests are constructed in both naturally occurring tree holes and abandoned nest holes made by large woodpeckers (like the pileated woodpecker). They also will nest in artificial nest boxes. Nest sites near water are highly favored. Saw-whet owls are typically monogamous but if the prey is plentiful the male will take more than one mate.

Females lay five or six white, oval eggs continuously incubating the clutch for 21 to 28 days. During this incubation period the male will bring the female food but will not incubate the eggs.

There have been instances of males caring for more than one female on nests at one time. The owlets grow very rapidly, though, and 18 days after egg hatching, the female begins to roost outside of the cavity. The fledged owlets roost together near the brood nest for the next four weeks and they are fed, by the male. The female may mate with another male and begin the rearing of a second clutch of eggs.

I read in a field guide that these tiny owls are practically bursting with attitude and nothing could be closer than the truth than this statement. What they lack in size they surely make up for with attitude.

But, then, I know some short people like that, too!

Jeannie Carl is a naturalist at the Carbon County Environmental Education Center, located at 151 E. White Bear Drive, Summit Hill. Call 570-645-8597 for information.