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Grasslands National Park of CanadaLearning Experiences"The Burrowing Owl"
The burrowing owl (Athene cunicularia hypugaea) is a species remarkably well adapted to the prairie environment. This small owl lives in abandoned Richardson's Ground Squirrel (gopher), prairie dog, fox, coyote, and badger holes. It's ground dwelling habits have earned its other common name: the ground owl. The burrowing owl has long legs and a typical owl-like head, that give it the means to keep a watchful eye on the prairie. It hunts all the time, consuming insects, snakes, frogs and beetles in the day and mice, voles, and other small mammals at night. It also prefers areas with longer grass to hunt in.
Figure 1. Range of the western burrowing owl (provided by Wellicome with forested/mountain regions deleted). Light shading delineates the current range (from Haug et al. 1993, updated with information from the 2nd burrowing owl symposium). The breeding range in the 1970s is indicated by the dotted lines (modified from Zarn 1974, updated with information from the 2nd burrowing owl symposium). Its subterranean habits are an adaptation to a treeless prairie environment. The burrowing owl prefers to live in short grazed prairie that offers plenty of holes for shelter. It prefers well-grazed prairie and pastures; sites with an open view. This is a species remarkably well adapted to an environment dominated by grazing animals (like cattle and bison), burrowing animals and an open, treeless habitat. Unfortunately, the burrowing owl has not fared well in a prairie environment dominated by agriculture and people. Once a common sight on the prairies, the burrowing owl population has been declining steadily since the 1930's. In 1979 the burrowing owl was first designated as a threatened species. In 1995 the status of the burrowing owl has declined from a threatened species to an endangered species facing imminent extirpation or extinction. Habitat loss and fragmentation, road kills, pesticides, food shortage, fewer burrow providers, and mortality on migration and wintering areas are the major factors contributing to its decline. Habits and HabitatBurrowing owls originally inhabited the four western provinces, with the majority of the population in Alberta and Saskatchewan. The populations in British Columbia and Manitoba are now extirpated with reintroduction being attempted at two sites in British Columbia with limited success. The current population in Saskatchewan and Alberta is estimated at fewer than 1,000 pairs. Two hundred of these pairs reside in Saskatchewan. The burrowing owl is distinguished from other owls by its small size, long legs and ground-dwelling habits. It is a migratory bird that travels as far south as southern Texas and northern Mexico in the winter months. Courting takes place when the owl returns to the Canadian prairies. After courting, the male begins to modify the burrow they have chosen to use. He lines the burrow with dried plants, feathers and cow dung, which is thought to aid in moderating the humidity and temperature of the burrow. Cow dung is also thought to aid in masking the scent of the owls. The female lays 6 to 12 eggs and incubates them for about four weeks. Two weeks after the owlets are born they begin venturing out of the safety of the burrow. After 3 weeks, they begin learning how to hunt. Burrowing owls do not dig their own burrows, but they modify the burrows of prairie dogs, badgers, Richardson's Ground Squirrels, coyotes, and even fox. When a predator approaches, the young retreat into the burrow and make a sound like that of a rattlesnake to frighten off intruders - a very effective strategy! The owls hunt within a 250 metre radius of their burrow during the day and will go as far as 2 - 3 km at night. They restrict the majority of their hunting to the morning and evening. They prey primarily on insects (grasshoppers, beetles, etc.) as well as mice, birds, snakes, and frogs. Predators of the burrowing owl include hawks, eagles, fox, coyote, badger, snakes, and domestic cats and dogs. What's HappeningThe major factor contributing to the decline of burrowing owls is habitat loss. Preferred prairie habitat for the burrowing owl is land that is also considered prime agricultural land. Only 20% of former native prairie remains undisturbed and, in areas such as the Regina Plains, less than 10% of native prairie remains undisturbed. As a result, burrowing owls in the Regina Plains area are not only occupying less productive areas of prairie but they are occupying sites such as ditches, culverts, railway allowances, farmyards and other sites that are exposed to traffic, spraying, cultivation and other dangers. In southwest Saskatchewan, lands such as the Prairie Farm Rehabilitation Administration (PFRA), private owned ranch lands, provincial community pastures and Grasslands National Park of Canada (GNP) now primarily form burrowing owl habitat. An equally grave danger to the owls is pesticides. Spraying for grasshoppers with chemicals like Furadan 480F (Carbofuran) significantly reduces the breeding success of the owls, decreases the availability of their prey, and reduces the number of burrowing mammals. Chemicals sprayed over the burrows often kill the owls, or lead to birth defects. Carbofuran interrupts the transmission of nerve impulses and it affects all forms of life. Wildlife will often mistake granules of carbofuran for food or grit, and it can be ingested while preening their feathers. Burrowing owls often consume contaminated grasshoppers, and ingest the poison. Carbofuran has been responsible for at least 50 major bird kills, involving thousands of birds.
Hoo Cares?Groups like Operation Burrowing Owl and areas like Grasslands National Park are working hard to protect both the owl and its habitat. Despite their efforts, the owl continues to be threatened by pesticide use and habitat loss. If you spot a burrowing owl, or have burrowing owls on your land and/or you would like to be involved in protecting them, then call: Operation Burrowing Owl toll free at 1-800-667- HOOT (4668). Give a hoot! For more information:Saskatchewan Burrowing Owl Interpretive Centre Operation Burrowing Owl Also visit these websites: Canadian Wildlife Service Website: Alberta Sustainable Resource Development Website: |
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