The Burrowing Owl (Athene cunicularia) is a small, long-legged owl found throughout open landscapes of North and South America. Burrowing Owls are well-known for nesting underground in burrows dug by mammals like prairie dogs, ground squirrels, and tortoises. They have many unique adaptations that allow them to thrive in grasslands and deserts across the Americas. In this article, we will explore what makes the Burrowing Owl such a distinctive and iconic bird.
Physical Description
Burrowing Owls are small owls, measuring 7-10 inches tall with wingspans of 20-24 inches. They have round heads with no ear tufts and bright yellow eyes. Their plumage is mottled brown, tan, and white which provides excellent camouflage against dirt and dry grass. When perched on the ground, Burrowing Owls often bob their bodies up and down or from side to side while scanning for prey.
Distinctive features of Burrowing Owls include their long legs and powerful talons which are well-adapted for running, pouncing on prey, and digging. Unlike most owls, Burrowing Owls have barely visibletassels on their heads rather than prominent ear tufts. They also lack the feathered “facial disk” that many owls have around their eyes and beaks to help direct sound towards their ears.
Habitat and Geographic Range
Burrowing Owls inhabit grasslands, prairies, deserts, and other open dry areas. They prefer landscapes with short vegetation and bare ground which provides visibility for hunting. Their geographic range extends across much of North and South America.
In North America, Burrowing Owls nest from southern Canada through the western and central United States into Florida. They are also found in parts of Mexico and many Caribbean islands.
Across South America, they are widely distributed from Tierra del Fuego up through central Brazil and northwestern Venezuela. Burrowing Owls are able to thrive in these diverse environments because of their adaptability to arid climates and treeless landscapes.
Underground Nesting and Burrows
The most distinctive feature of Burrowing Owls is their underground nesting behavior. Unlike most owls which nest in cavities or tree hollows, Burrowing Owls utilize abandoned burrows dug by ground-dwelling mammals.
Suitable burrows used by the owls are often dug by prairie dogs, ground squirrels, tortoises, or badgers. Burrowing Owls may also excavate their own burrow in softer soils, modify an existing burrow, or use artificial burrows provided by conservation programs.
Typical burrow depths are 2-3 feet below ground. The owls line their nests with materials like dung, plant debris, feathers, and other objects. Living underground provides shelter and protection for Burrowing Owl chicks and adults. It also helps moderate temperature extremes in grassland environments.
Diet
Burrowing Owls are opportunistic hunters and eat a wide variety of prey. Common foods include insects like beetles, grasshoppers, moths, crickets, and scorpions. They also prey on small mammals such as mice, voles, rats, gophers, and ground squirrels. Other food sources are amphibians, reptiles, young rattlesnakes, small birds, eggs, and carrion.
Burrowing Owls employ a “sit and wait” hunting strategy from a perch or the ground. They scan for prey with their keen vision and then swoop down to catch victims with their talons before returning to their perch. Leftover prey items are often cached at burrow entrances for later consumption.
Breeding and Reproduction
The breeding season for Burrowing Owls varies across their range. In warmer southern regions, they can breed nearly year-round. Further north, breeding typically takes place between March and August.
Burrowing Owls are predominantly monogamous. The female lays a clutch of 6-12 white eggs within the burrow. She alone incubates the eggs for 3-4 weeks while the male provides food. Hatchlings are covered in white down and cared for by both parents for another 3-4 weeks.
Young owlets emerge from the burrow after about 2 weeks and remain close by while learning to hunt. After 7-8 weeks, the juveniles leave the natal burrow but may remain loosely associated with the parents until migrating or establishing their own territory. Burrowing Owls can raise more than one brood per year.
Unique Behaviors and Vocalizations
Burrowing Owls exhibit many interesting behaviors and adaptations:
– Sunning – Perching at burrow entrance and spreading wings to absorb heat in morning light. Thought to aid metabolism and circulation.
– Decorating – Adorning burrow entrance with dung, feathers, foil, bones, and other objects for unclear reasons.
– Wing-flapping – Unusual downward flapping of wings used in courtship displays and to signal alarm. Also used by begging hatchlings.
– Bobbing – Frequent vertical head-bobbing motion used perhaps for better depth perception and prey detection.
– Mobbing – Aggressive swooping dives at predators that get too close like hawks, badgers, or coyotes. Done to defend nest.
Vocalizations include a range of hisses, barks, raspy calls, and other noises. The male’s “coo-coo” mating call is commonly heard at dawn and dusk during breeding season. Young owlets make raspy begging calls when waiting for food delivery.
Migration and Territoriality
Northern populations of Burrowing Owls are migratory, moving southwards in fall from Canada and the northern U.S. before returning to breeding grounds in spring. Owls from further south are often year-round residents.
Burrowing Owls are highly territorial and defend areas around their burrow. In prime habitat, densities can reach 35 pairs per square kilometer but are often lower. Territories range from 0.1 to 6 hectares depending on resources and population density.
Some juveniles and adults disperse over large distances before settling into new areas. Banding studies show Burrowing Owls capable of migrating up to 1,500 kilometers between breeding and wintering sites.
Conservation Status and Threats
Burrowing Owls are listed as endangered in Canada and a Species of Special Concern in Mexico. In the United States, population declines have led many states to list them as endangered, threatened, or a species of concern.
These owls face a number of serious threats contributing to declining populations:
– Habitat loss – Plowing and urban expansion of prairies and grasslands.
– Control of burrowing mammals – Elimination of prairie dogs and ground squirrels.
– Vehicle collisions – Owls are attracted to roadside verges.
– Pesticides – Can accumulate in prey and poison owls.
– Climate change – Increased droughts and severe weather events.
Conservation efforts focus on habitat protection and creation of artificial burrows. Public education campaigns help reduce vehicle strikes. Continued monitoring and mitigation of threats are needed to protect Burrowing Owl populations.
Cultural Significance of Burrowing Owls
Burrowing Owls hold a place in Native American culture, mythology, and oral traditions. Known as the “ground owl” to tribes like the Navajo, these owls were respected for their ties to the earth and underground world.
Feathers and imagery of Burrowing Owls were believed to hold symbolic meaning and spiritual power among some tribes. Legends featuring the owls have been passed down among Indigenous peoples of the Americas.
Today, Burrowing Owls remain a significant indicator species of prairie ecosystem health. They continue to inspire conservation efforts through research, education programs, and citizen science. As a charismatic grassland bird, the Burrowing Owl serves as an important ambassador for sustainable land management practices across the Americas.
Fun Facts
- Burrowing Owls have bright yellow eyes; most owls have yellow or orange
- They are the only owl species that regularly lives and nests underground
- Found in grasslands and deserts from Canada to Argentina
- Weigh only 5-8 ounces (140-240 grams) – smaller than a robin!
- Primarily eat insects, small mammals, reptiles, amphibians, and birds
- A group of owls is called a “parliament”
- Once lined nests with bison and cattle dung which led to “Billy owl” nickname
- Have average lifespan of 5-6 years in wild, up to 10 in captivity
- Males attract mates with “coo-coo” call and by presenting food gifts
- Young owlets hiss and jab with claws in defense when threatened
Conclusion
The unique burrowing habits, subterranean nesting, adaptable hunting behaviors, and charismatic nature of the Burrowing Owl highlight why they are so special. Their cultural significance and importance as an indicator of prairie ecosystem health also makes them a valuable species. Though facing concerning declines from human impacts, targeted conservation efforts combined with more sustainable land management practices can ensure Burrowing Owls continue thriving across the diverse landscapes of the Americas for generations to come.
