Bird counts
The National Audubon Society’s 125th Christmas Bird Count will be held through Jan. 5. Today we show you some of California’s owls, particularly the burrowing owl, a candidate for the state’s endangered species list.
RELATED: How a surprising San Jose spot became a last refuge for the Bay Area’s burrowing owl population
Frank Chapman and 26 other naturalists initiated the Christmas Bird Count in 1990 as a way of promoting conservation by counting, rather than hunting, birds on Christmas Day. Some counts have been running every year since, and the phenomenon has spread to more than 20 countries in the Western Hemisphere. You can sign up for the count at audubon.org.
You can learn more about the bird count here.
On March 5, the Center for Biological Diversity, Defenders of Wildlife, Burrowing Owl Preservation Society, Santa Clara Valley Audubon Society, Urban Bird Foundation, Central Valley Bird Club and the San Bernardino Valley Audubon Society submitted a petition to the California Fish and Game Commission to list the western burrowing owl as a threatened or endangered species. The commission published the findings of its decision to make the species a candidate for listing in October, and the western burrowing owl now receives the same legal protection afforded to an endangered or threatened species. As of Oct. 25, California’s Department of Fish and Wildlife had a year to conduct a status review that will inform the commission’s final decision.
Because burrowing owls spend so much time on the ground and nest underground, a major threat to the species is nest predation. The scientific name of the burrowing owl is Athene cunicularia. “Cunicularia” means “to mine” or “burrow” in Latin.
According to the nonprofit Center for Biological Diversity, burrowing owls have been eliminated as a breeding species from “almost all” of the California coast and are “rapidly” facing localized extinction in the Bay Area, where less than 25 breeding pairs remain.
Burrowing owls have been eliminated or are nearly wiped out as a breeding species in nearly one-third of their former range in California.
Range in North America
Observation tips
Burrowing owls arrive at their breeding grounds in March throughout the western Great Plains and southern Florida and begin to migrate south in August and September. They use open grasslands, deserts, prairies and agricultural areas, and can often be seen perched on fence posts looking for prey and keeping an eye on predators. Burrowing owls prefer grasslands grazed heavily by cattle or prairie dogs. They are very well camouflaged and amazingly small, given the wide-open areas where they live. The best chances for seeing them are at dawn or dusk. They often reuse nesting sites and may return to the same breeding area for multiple years.
Ideal habitat
Throughout the West, the burrows they use most commonly for nesting are in black-tailed prairie dog colonies. Owls depend on these mammals for maintaining the burrow structure for breeding success. When burrowing mammals are eradicated, owls will abandon the area. The surrounding landscape is primarily short grass pasture or heavily grazed mixed-grass prairie where vegetation is more than 4 inches tall on gently sloping areas with less than 50% herbaceous cover and with few trees (less than 5%). Because owls forage in tall grass (small rodents hide in taller grass), and nest and roost in short grass areas, a mosaic of habitats close by is important. They seem to prefer black-tailed over white-tailed prairie dog colonies, presumably because the habitat is more open and vegetation is shorter. They sometimes concentrate their nests at the edges of prairie dog colonies, where the birds may benefit from increased perch availability and high insect populations
Some of California’s owls by size
California is home to at least 16 owl species. According to California’s Department Fish and Wildlife, the northern spotted owl populations are in serious decline due to competition from the invasive and nonnative barred owl. Barred owls are larger and more aggressive and have a broader suite of prey and habitat preferences than spotted owls. A study is being conducted on a rangewide experimental barred owl removal.
Sources: U.S. Fish and Wildlife, California Department of Fish and Wildllife, wildcalifornia.org, Center for Biological Diversity, The Birds of North America Online and the Cornell Lab of Ornithology, Owlresearchinstitute.org