Burrowing owl, endangered species, Canadian species

Athene cunicularia

WPC first became involved in burrowing owl recovery in Saskatchewan in 1995. Between 1995 and 2002, WPC established a small captive breeding colony in the province and developed a novel “soft-release” technique for releasing captive-bred owls into the wild. The “soft-release” method involves pairing young captive-raised owls in small field enclosures and releasing them as a pair after they have initiated their first clutch. Today we are participating in a burrowing owl reintroduction program in British Columbia’s Nicola Valley, where recovery efforts have been ongoing since 1992. In 2005, research into the “soft-release” technique showed that 20% more owls remained at the release site, 14% more survived the breeding season, and 20% more young were produced than when the traditional “hard-release” technique was employed. Since 2005, the BC Recovery Team has employed this successful technique and in 2010, 20% of our banded owls returned to the Nicola Valley – the highest number to ever return!

In the spring of 2010, 23 burrowing owls returned to B.C. from migration, the largest number observed since the recovery program began. Highlights of the 2011 program included:

Opening a third breeding centre to support the expansion of the program into the South Okanagan region.
Developing a network of contacts throughout the western United States to learn more about the threats and opportunities for migrating owls.
Using geolocator dataloggers to learn more about the owls’ migratory habits.

Description

The burrowing owl, distinguished by its very long legs and short tail, is one of the smallest owl species. It gets its name from nesting in burrows dug by animals such as ground squirrels, badgers and prairie dogs. Burrowing owls are also known as “Howdy Owls” because of their habit of bobbing up and down in a bowing motion, a behaviour that likely allows them to determine distance from multiple viewpoints. Young owls in the nest make a rattling sound similar to rattlesnakes to ward off predators.

Burrowing owls in the northern part of their range migrate south for the winter. They are nocturnal (active at night), although unlike other owls, they are somewhat active during the day. Burrowing owls feed on rodents, large insects (such as crickets, beetles and grasshoppers), and small reptiles and amphibians. They breed in spring, laying 6-12 eggs. About 50% of hatchlings survive, taking 40-45 days to fledge.

Habitat

Burrowing owls can be found in prairie grasslands and require open areas with low ground cover, burrows created by ground squirrels and prairie dogs for nesting, and abundant food to support family groups.

Distribution and Population Size

Burrowing owls were historically found in the grasslands of central and southwestern Canada, central and southern United States and Mexico, and South America. In Canada, the burrowing owl has virtually disappeared from Manitoba and British Columbia. Throughout their remaining range, they exist in greatly diminished numbers in isolated fragments. Fewer than 1,000 pairs are thought to exist in Canada.

Threats to survival

Habitat loss and fragmentation are the main reasons for the species decline – shortgrass prairie habitats are increasingly converted to agricultural crop production. In addition, efforts by farmers to reduce ground squirrels, prairie dogs and insects diminish available burrows used for nesting, roosting sites and food sources, especially during migration. Moreover, the use of pesticides to eliminate insects, ground squirrels and foxes results in poisoning of owls when carcasses are consumed. Of particular concern is the use of Carbofuran, a potent insecticide used to control grasshoppers, one of the owls’ primary food sources. Carbofuran bioaccummulates and leads to reduced nest success. Badgers, foxes, skunks, weasels and snakes can also greatly reduce nesting success by preying on eggs and young, and adults can be predated by coyotes and raptors, namely red-tailed hawks.