The burrowing owl (Athene cunicularia) is an unusual bird of prey, easily recognizable by its long legs and habit of living underground, unlike most other owl species. These small owls inhabit open grasslands and prairies across North and South America, spending significant time walking or running on the ground rather than solely flying. Despite their wide geographic range, the North American population is experiencing rapid and sustained declines, leading to concerns about the species’ long-term survival. This population reduction is primarily driven by factors that disrupt their unique lifestyle, including the loss of their natural habitat and the elimination of the animals they rely on for shelter.
The Burrowing Owl’s Unique Dependence on Burrow Habitats
The burrowing owl is fundamentally connected to the activities of other species, a relationship known as obligate commensalism. These owls are not efficient diggers themselves, so they rely almost entirely on the existing underground tunnels excavated by fossorial mammals. This unique dependence means the owl’s shelter infrastructure is controlled by the health and distribution of species like prairie dogs, ground squirrels, badgers, and marmots. Burrowing owls utilize these tunnels for nesting, roosting, and protecting their young from predators and extreme weather. The presence of active colonies of burrowing mammals, particularly prairie dogs, is strongly correlated with higher owl productivity and survival, as the constant maintenance keeps the tunnels clear and structurally sound.
Habitat Loss and Fragmentation
The physical removal and division of natural habitats represent one of the most significant threats to the burrowing owl population across its range. These owls require vast, open areas with short, sparse vegetation, typically found in native grasslands and prairies. The conversion of these ecosystems, largely driven by intensive human land use, directly eliminates suitable breeding and foraging grounds. Large-scale agricultural practices, specifically the plowing of native prairie for crop production, destroy the surface habitat and eliminate the subterranean infrastructure provided by burrowing mammals. Rapid suburban and urban development further exacerbates this issue, leading to the physical destruction of burrows and the displacement of owl colonies, resulting in fragmented and isolated populations that hinder genetic diversity and recovery.
Indirect and Direct Human Interference
Beyond habitat loss, specific human activities result in the direct mortality of the owls or the indirect elimination of their necessary resources. A major factor is the widespread use of pest control measures targeting the mammals that create and maintain the owls’ burrows. Ranchers and agricultural operations often view prairie dogs and ground squirrels as pests, leading to organized eradication programs using poisons, shooting, and gassing. The elimination of these burrow-providing species removes the foundation of the owl’s living infrastructure, leading to nesting failure or forcing owls to move to less suitable areas. Furthermore, the use of rodenticides creates a significant risk of secondary poisoning for the owls themselves, as they consume rodents that may have ingested the poison; additional direct mortality factors include collisions with vehicles and intentional harassment near human settlements.
Current Conservation Status and Geographic Scope of Decline
The conservation status of the burrowing owl varies across its North American range, reflecting regional population declines. Federally, the species is protected in the United States, Canada, and Mexico under the Migratory Bird Treaty Act and is considered a Bird of Conservation Concern by the U.S. Fish and Wildlife Service. However, it is not listed under the U.S. Endangered Species Act. At the state and provincial levels, the status is often more severe, reflecting local extirpations and drastic population reductions. The decline is most pronounced in the northern parts of its range, with Canadian populations experiencing severe reductions, and significant drops also noted in areas like coastal California and the Dakotas.
State and Provincial Listings
The species is classified as:
- Endangered in Canada and in U.S. states like Minnesota.
- Threatened in states such as Colorado and Florida.
- A Species of Concern in many western states, including California, Oregon, and Washington.
Effective conservation efforts must therefore be integrated, protecting both the remaining habitat and the essential burrow-creating species upon which the owls depend.