Western Burrowing Owl
The Burrowing Owl is a species of small owl ranging in size from 19.5 to 25 cm and weighing approximately 150g. They have round heads, short feathers, long legs, yellow eyes, and have a largely brown coloring with white streaks or spots. Cowboys are known to have called them “howdy birds” due to their tendency to bob their heads from the entrance to their burrows.
Burrowing Owls can be found in the Western United States, Florida, Canada, Mexico, Central America, and the Caribbean. The San Francisco bay area support both resident populations of Western Burrowing Owls and overwintering populations. Western burrowing owls are observed on Stanford lands from roughly November through March each year.
Burrowing Owls live in treeless areas with low and sparse vegetation. They are usually found in grasslands, deserts, and steppe landscapes, and often live near burrowing mammals like prairie dogs, ground squirrels, armadillos, and tortoises. Burrowing Owls in the west use burrows dug by other animals as sites for their nests and non-migrating owls use them year-round. They prefer burrows with elevated positioning to avoid flooding, loose soil, and nearby structures like mounds or fences to use as a lookout.
Community relationships and behavior
Burrowing Owls hunt both night and day and use a selection of methods, including swooping down from above or running on the ground and using their talons to catch prey. Their diet varies depending on the season and location, but they mostly eat insects, amphibians, and small mammals.
They largely mate with a single partner for life and tend to breed close together in loose communities. Burrowing Owl males will court a female partner by flying dozens of feet into the area, hovering for a moment, then quickly descending. Partnered owls vocalize, rub bills, and preen each other.
Burrowing Owls in the west usually lay between 7 and 10 eggs and incubation lasts between 28 and 30 days, during which the male brings food to the female. After hatching the female will remain with her young most of the time and begin hunting after 1 to 2 weeks. Chicks typically leave the nest after 6 weeks.
Natural predators of Burrowing Owls include badgers, domestic house cats, weasels, skunks, domestic dogs, coyotes, snakes, bobcats, Great Horned Owls, American Crows, Swainson’s, Ferruginous, Red-tailed, and Cooper’s hawks, and Merlin, PraIrie, and Peregrine falcons.
Burrowing Owls are a California Species of Special Concern. They are estimated to have a breeding population of 2 million individuals, but their total numbers have declined by 33% between 1965 and 2016. Habitat loss and fragmentation of grassland habitat largely due to agriculture and urban development are the primary threats for the species. Declines in populations of burrowing mammals have also contributed to Burrowing Owls’ loss of suitable habitat. Conservation legislation and habitat protection programs have helped stabilize Burrowing Owl populations, but climate change will likely reshape and decrease the species’ livable range.
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