The burrowing owl (Athene cunicularia) is a small, long-legged bird that stands apart from its tree-dwelling relatives. Found across a wide range spanning from the grasslands of Canada to the open landscapes of South America, this unique bird is an indicator species for the health of prairie ecosystems. Despite its broad geographical reach, the owl’s population is declining rapidly across much of North America, leading to various conservation designations and significant concern for its long-term survival.
Unique Ecological Dependency
Unlike most owl species that build nests in trees or cavities, the burrowing owl is entirely dependent on other animals for its home. This makes the owl’s survival intrinsically tied to the abundance of burrowing mammals. The owls primarily rely on abandoned burrows excavated by prairie dogs (Cynomys spp.), ground squirrels, badgers (Taxidea taxus), and even tortoises.
The owls cannot dig their own deep, secure nesting tunnels in hard-packed prairie soil. Instead, they occupy and maintain these pre-existing underground structures, which offer protection from predators and temperature moderation. This reliance creates a fragile ecological link where the persecution of one species directly harms the owl’s ability to successfully breed and survive.
Loss and Fragmentation of Essential Grassland Habitats
The largest threat driving the burrowing owl’s decline is the widespread destruction and alteration of its natural habitat. The owls require expansive, open short-grass and mixed-grass prairies with low vegetation cover to effectively hunt and spot approaching predators. These grasslands are among the most converted biomes globally due to human land use.
Conversion to monoculture agriculture, such as fields of wheat or corn, eliminates the necessary open structure and destroys the underground network of burrows. Urban development and infrastructure expansion, including roads and energy projects, permanently remove large tracts of prairie land. This outright loss is compounded by habitat fragmentation, where remaining patches of suitable grassland become isolated.
Breaking up the landscape isolates owl populations, preventing dispersal to new areas and limiting the movement of mates. Small, isolated populations become genetically vulnerable and are less resilient to localized threats like disease or severe weather events. For instance, the conversion of grasslands into dense cropland makes former territories unusable for the owls.
Eradication of Necessary Ecosystem Partners and Prey
The burrowing owl’s plight is worsened by resource management practices that target its support system. Ranchers and farmers have historically viewed burrowing mammals, especially prairie dogs and ground squirrels, as agricultural pests that compete with livestock or damage equipment. This perception has led to systematic eradication and poisoning campaigns against these host species across the Great Plains.
The removal of burrowing mammals creates a significant barrier to nesting success by eliminating housing infrastructure. Furthermore, the widespread use of rodenticides and pesticides creates indirect threats to the owls themselves. Burrowing owls prey heavily on insects like grasshoppers and small mammals, and they can suffer secondary poisoning by consuming contaminated prey or carcasses. The use of powerful insecticides, such as Carbofuran, is a concern because it drastically reduces the insect prey base while also posing a direct poisoning risk.
Current Conservation Status and Recovery Efforts
The legal status of the burrowing owl varies significantly across its range. It is listed as endangered in Canada and is protected in the United States under the Migratory Bird Treaty Act. Various states further designate the species as threatened (e.g., Colorado and Florida) or a species of special concern (e.g., California and Montana). The species is also listed in CITES Appendix II, which regulates international trade.
Recovery efforts focus on human intervention to reverse the decline caused by habitat and host species loss. One common strategy involves installing artificial burrows, typically using plastic tubing and chambers, to provide immediate housing in suitable habitats. Translocation and “head-starting” programs are also underway, where young owls are raised in captivity and released into protected areas to boost local numbers. Conservation programs increasingly advocate for prairie dog management reform to protect the host colonies foundational to the owl’s survival.