TOP 5 ID TIPS: BURROWING OWLS
Usually spotted on the ground
Distinctive white eyebrow and round head
Medium in size
Blends into grassy, sandy habitats
© Ly Dang / nature2pixels.com
Greeting cards, Facebook videos, and TV commercials have made this seemingly comical little owl a celebrity. Perhaps you already recognize the species from the media!
Burrowing Owls are found throughout North and South America; however, the species has been experiencing declines overall since the 1930s. It is now listed as “endangered” in Canada, “Species of Special Concern”, and on the “threatened” list in nine of the western states of the U.S. Fortunately, their quirky expressions and behaviors have won the hearts of many, increasing conservation efforts to help preserve their habitat.
© Kurt Lindsay
© Danny Hancock
BURROWING OWL HOMES
Unlike other owls, the Burrowing Owl does not rely on trees for nest sites. Instead, this bird does exactly what its common name suggests; it burrows! The scientific name of the Burrowing Owl, “Athene cunicularia”, actually reflects on this extremely unique characteristic as well. “Cunicularia” means to “mine” or “burrow” in Latin.
This owl nests underground, in abandoned burrows of small mammals like badgers, prairie dogs, skunks, marmots, and other animals, like tortoises. If there are no preexisting burrows around for nesting, Burrowing Owls may excavate their own nest burrows, although some scientists believe there is a correlation with nest failures and newly dug burrows. Burrowing Owls often create mounds around the entrance to their dens, if there is not a preexisting one. This may be their way of keeping the den from flooding.
The underground nest of a Burrowing Owl moderates temperatures and keeps the owls from becoming dehydrated on hot days. Dens can become quite stuffy, however, due to a lack of airflow. This is one reason scientists believe Burrowing Owls are more resistant to higher concentrations of carbon dioxide than other owls. Such resistance would allow them to function normally in a stuffy den, where fresh, oxygenated air is not abundant.
These dens, despite having a slight shortage of fresh air, are quite cozy for the owls! The female owl will often line the nest and burrow with dried livestock manure. This might not sound comfortable to us, but it serves several purposes for the owls: to hide the owl’s scent from predators, attract insects (which the owls can eat) to the den, and signals to other owls, “Hey! This burrow is taken!”. Sadly, these owls have also been known to line nests with human trash; cigarette butts, tin foil, shredded paper, plastics, and other litter has been discovered in Burrowing Owl dens.
© Danny Hancock
© Kurt Lindsay
BURROWING OWL CHICKS
Young Burrowing Owls are quite comical and playful, making them ideal subjects for photographers. You may have seen videos of these nestlings turning their heads almost completely upside down, or playing “Hide ‘n’ Seek” with the camera.
Juvenile Burrowing Owls can be differentiated from adults of the species by their cream or tan-colored downy feathers. The underdeveloped plumage gives them a plump appearance and makes them look like tottering fluffballs.
Indeed, Burrowing Owl chicks seem to be easily entertained and can be seen pouncing on eachother or prey. Some scientists believe this is a form of play, but more importantly, a way to develop hunting skills.
While Burrowing Owl chicks are developing their hunting and defense skills, they are somewhat helpless in the burrow. Survival rates of these owlets is estimated to be mere 20 - 30% for the first year, even though the mother owl keeps a close eye on the nest. However, young Burrowing Owls have developed a tactic to ward off potential predators. To scare off badgers, humans, and any other threats, the chicks actually mimic the sound of a rattlesnake! Since the intruder can not see them, it will be scared off by the sound of the “snake” it hears. This unique defense call has been recorded by scientists and is now stored in the famous Macaulay Library.
Contrary to popular belief, these owls do not share dens with rattlesnakes.
© Kurt Lindsay
Burrowing Owls have been known to nest in many areas, but nearly all nest sites for the species are in grassland areas. Because the species has been experiencing steady declines, some have begun installing artificial burrows in attempt to create new nest sites. positioning these along agricultural fields, golf courses, cemeteries, road allowances, airports, abandoned urban lots, and fairgrounds have provided many homes for Burrowing Owls in recent years throughout North America. Note that many of these are also common homes for small ground mammals. There is a strong ecological relationship - which you’ve probably already picked up on - between Burrowing Owls and small underground-living mammals.
Although small mammals often provide burrows for these owls, they don’t always leave the place clean. Over 15 species of fleas have been found to live in Burrowing Owl dens. Also, even though badgers often leave their nests as perfect nest sites for Burrowing Owls, Badgers are known to be predators of the species. In fact, some studies state that up to 90% of Burrowing Owl nest predation was carried out by Badgers (in certain areas).
Small mammals often live in colonies; the famous example of this is “a colony of prairie dogs”. As a result, Burrowing Owls can be found in colonies as well. Burrowing Owl colonies can grow large, although this is increasingly rare. At one time in the 1880s in Florida, a colony was reported as being “three-miles long and home to hundreds of pairs of owls”. Today, seeing a colony of Burrowing Owls is a treat for anyone, even if the colony is relatively small!
Burrowing Owl Hunting & Prey
Throughout the years, there has been much debate over the Burrowing Owl’s ability to fly. Although this bird can fly and does migrate in certain areas, the Burrowing Owl is often considered a less-efficient flyer than other owls due to the fact that they spend most of their time on the ground. Since they don’t like to fly as much as other owls, these birds scamper across their prairies and grasslands, attempting to catch insects, like grasshoppers and beetles. When these prove difficult to catch, Burrowing Owls will hunt for larger prey, like voles and other tiny mammals. Some studies suggest that these small mammals are actually a preferred prey type for Burrowing Owls, despite the fact that they usually end up eating insects. Prairie dogs and similar-sized small mammals are too large for Burrowing Owls to hunt, even though they take over these animals’ burrows.
© Kurt Lindsay
Burrowing Owl Threats
A variety of threats and dangers have contributed to declines in North American Burrowing Owl populations. These birds now inhabit just ⅓ of their original range in Canada and are listed as endangered.
Because Burrowing Owls spend so much time on the ground and nest underground, a major threat to the species is nest predation. As previously mentioned, badgers are common killers of young Burrowing Owls. Additionally, domestic cats and dogs, weasels, skunks, hawks, other species of owl, falcons, and crows have been known to kill Burrowing Owls and their young.
Many agricultural practices harm Burrowing Owls as well. Farmers and ranchers often kill burrowing rodents. Whether it be to keep them away from crops, prevent disease, or keep cows from breaking their legs by tripping in the rodent holes, farmers and ranchers have good reason to initiate rodent control. However, this has lead to an overall decrease in North American small mammal populations, leaving the Burrowing Owl with fewer and fewer nest sites. In addition, agricultural pesticide and rodenticide toxicity are smaller threats.
Cannibalism has also been reported in Burrowing Owls. Cases of them consuming a found-dead carcass, as well as killing another Burrowing Owl and consuming it, have been recorded.
© Danny Hancock
© Danny Hancock
BURROWING OWL BEHAVIOR
These owls often appear curious and comical. While trotting after and pouncing on bugs in the prairie, they can put on quite a show day or night. Rain also seems to excite them; reports have stated that the owls stretch and flap their wings, run around, shake their feathers, and preen during rain showers.
Although these owls do not nest in trees, they occasionally perch in them to hunt, or roost in them while napping. At other times, they might roost on top of the mound surrounding their burrow entrance.
While some owls remain in pairs year-round, like the Barn Owl, these owls do not. During the winter, pairs split up and individuals “fly solo”.
Burrowing Owls have become famous for bobbing their heads up and down; videos of this behavior have gone viral across many media platforms. However, what most people do not know is that this action only occurs when the owl is disturbed by something. Perhaps it is another animal or owl, a machine or car, or the human taking the video. No matter what the disturbance is, these owls will bob their heads up and down, probably in attempt to hear the intruder better, before taking defensive action.
BURROWING OWL APPEARANCE
Male and female Burrowing Owls are virtually indistinguishable. They are similar in color, shape, and size. However, the male Burrowing Owl tends to be about 3% larger than the female. This is odd for a raptor (owls are classified as raptors, along with falcons, hawks, and other Birds of Prey). In nearly all species of raptors, females are larger than males, which is known as “reverse sexual dimorphism”). Since the males are larger in this species, it is known simply as “sexual dimorphism”.
Leucism is a unique and rare condition amongst owls, but has been reported in this species, the Great Horned Owl, Western Screech Owl, Great Gray Owl, Short-eared Owl, and some non-North American owls. While there are few studies on this topic, most commonly leucism is an inherited genetic condition in which a mutant type (allele) for a gene is expressed. This causes a disruption in the pigments produced during feather development.
It is important to note that leucism is not albinism. The difference between these two is that albinism is the loss of ALL pigments in ALL body parts and causes a reduction in visual abilities for that reason. Leucism is the lack of pigments in parts of the body. In many cases of avian (bird) leucism, the eyes, legs, and bill will not be affected by the morph in coloration. They will still have their usual pigments.
As you can see, the leucistic Burrowing Owl shown here lacks pigments in some feathers - especially those on its head - and a slight discoloration in the bill. This owl’s eyes still appear to be pigmented, so its eyesight may not be significantly affected by its leucism.
Different species of owl have been reported breeding successfully when one or both of the parents are leucistic. However, more studies are needed before anyone can say leucism does not affect breeding abilities or survival.
© Ly Dang
© Danny Hancock
BURROWING OWL FACTS:
A small, long-legged owl with bright yellow eyes and broad, white eyebrow
Males: head, back, and chest are brown with white spotting, belly white with dark barring
Females: similar to male, but with heavier barring and spotting
Young: less barring; brown chest, buff colored belly
Ground Owl, Prairie Dog Owl, Gopher Owl, Cuckoo Owl
BURROWING OWL SIZE:
Height: Males 19-25 cm (7.5-9.8 in), Females 19-25 cm (7.5-9.8 in)
Weight: Males 150g (5.29 oz), Females 150g (5.29 oz)
Wingspan Both: 50-60 cm (19.6-23.6 in)
BURROWING OWL RANGE:
Ranges from southern Canada all the way through South America; also found on Caribbean Islands
BURROWING OWL HABITAT:
Dry, open areas: grasslands, savannas, deserts, farmland; even golf courses, cemeteries, vacant lots, and other flat, open grounds within towns and cities
BURROWING OWL DIET:
Arthropods like beetles, crickets, and scorpions; small mammals such as voles; sometimes reptiles and amphibians
BURROWING OWL VOICE:
When disturbed in the nest, will imitate the sound of a rattle snake to scare off predators
Males: a soft coo coooo or a multi-noted warbled batch of coos; also a series of high-pitched, raspy “chack” or “cheh” notes
Females: a series of down-slurred notes or a warble
BURROWING OWL NESTING:
Nest Site: in burrow in flat or slightly elevated areas; burrows are usually made by mammals like ground squirrels, prairie dogs, badgers, etc,
and are “renovated” by the owl
Eggs: 6-11 eggs
Incubation: 28-30 days
BURROWING OWL HUNTING HABITS:
Usually crepuscular, but can be found hunting anytime of day or night; walks, hops, or runs on the ground after prey; also hunts from perch; sometimes caches prey in or around burrow
BURROWING OWL CONSERVATION STATUS:
Not globally threatened, but listed as Endangered in some U.S. states and parts of Canada, a Species of Special Concern in parts of U.S., and Threatened in parts of Canada.
BURROWING OWL DISTRIBUTION IN NORTH AMERICA
Maps provided by The Birds of North America Online and the Cornell Lab of Ornithology.
A bird living under ground? This must be a joke!
But it’s true; the Burrowing Owl of North America’s flatlands really does spend time underground! This owl nests in the burrows made by prairie dogs, badgers, skunks, and other small mammals. But don’t come a knockin’ on its door; when disturbed in its burrow, the Burrowing Owl lets out an alarm call sounding very much like the shake of a rattlesnake’s rattle; that’s sure to scare off any would be predators!
Though quite at home beneath the earth’s surface, the Burrowing Owl doesn’t stay underground all the time. It spends time above ground hunting for tasty prey like insects and rodents. Though the Burrowing Owl can fly, it prefers to hunt on foot, pursuing its prey by walking, hoppi ng, or running after it. Wouldn’t that be a site to see?
Owl Research Institute © All Rights Reserved
Edited and arranged by Brooklin Hunt, VA, ORI Intern
Nogueira, Denise M, & Alves, Maria Alice S. (2011). A case of leucism in the burrowing owl Athene cunicularia (Aves: Strigiformes) with confirmation of species identity using cytogenetic analysis. Zoologia (Curitiba), 28(1), 53-57.