Burrowing Owl

Burrowing owls (Athene cunicularia) are so named because they live underground in burrows that have been dug out by small mammals like ground squirrels and prairie dogs. They are covered in brown spotted feathers and have long legs. They also sport distinctive white “eyebrows” above bright yellow eyes. They are one of the smallest owls in North America.

Diet

Burrowing owls eat small mammals such as moles and mice during late spring and early summer. Later they switch to insects, especially grasshoppers and beetles. Burrowing owls are also known to eat birds, amphibians and reptiles.

Population

Current burrowing owl population estimates are not well known but trend data suggests significant declines across their range. Most recent official estimates place them at less than 10,000 breeding pairs.

Range

Burrowing owls are distributed from the Mississippi to the Pacific and from the Canadian prairie provinces into South America. They are also found in Florida and the Caribbean islands. Burrowing owls have disappeared from much of their historic range.

Behavior

Unlike other owls, burrowing owls are active during the day, especially in the spring when they gather food for their large broods. This species of owl prefers open areas with low ground cover. They can often be found perching near their burrow on fence posts and trees. Burrowing owls make a tremulous chuckling or chattering call. They also bob their heads to express excitement or distress. Burrowing owls often nest in loose colonies about 100 yards apart.

During the nesting season, burrowing owls will collect a wide variety of materials to line their nest, some of which are left around the entrance to the burrow. The most common material is mammal dung, usually from cattle. At one time it was incorrectly thought that the dung helped to mask the scent of the juvenile owls, but researchers now believe the dung helps to control the microclimate inside the burrow and to attract insects, which the owls may eat.

Reproduction

The nesting season begins in late March or April in North America. Burrowing owls usually only have one mate but occasionally a male will have two mates. Pairs of owls will sometimes nest in loose colonies. Their typical breeding habitat is open grassland or prairie, but they can occasionally adapt to other open areas like airports, golf courses, and agricultural fields. Burrowing owls are slightly tolerant of human presence, often nesting near roads, farms, homes, and regularly maintained irrigation canals.

The owls nest in an underground burrow, hence the name burrowing owl. If burrows are unavailable and the soil is not hard or rocky, the owls may excavate their own. Burrowing owls will also nest in shallow, underground, man-made structures that have easy access to the surface.

During the nesting season, burrowing owls will collect a wide variety of materials to line their nest, some of which are left around the entrance to the burrow. The most common material is mammal dung, usually from cattle. At one time it was thought that the dung helped to mask the scent of the juvenile owls, but researchers now believe the dung helps to control the microclimate inside the burrow and to attract insects, which the owls may eat.

The female will lay an egg every one or two days until she has completed a clutch, which can consist of 4 to 12 eggs (usually 9). She will then incubate the eggs for three to four weeks while the male brings her food. After the eggs hatch, both parents will feed the chicks. Four weeks after hatching, the chicks can make short flights and begin leaving the nest burrow. The parents will still help feed the chicks for one to three months. While most of the eggs will hatch, only four to five chicks usually survive to leave the nest.

Site fidelity rates appear to vary among populations. In some locations, owls will frequently reuse a nest several years in a row. Owls in migratory northern populations are less likely to return to the same burrow every year. Also, as with many other birds, the female owls are more likely to disperse to a different site than are male owls.