Friday, September 24, 2010

California's Largest Burrowing Owl Population in Rapid Decline

We usually write about efforts to protect the endangered burrowing owl population here is Canada, but now, news that the species is in severe decline in California. From the Center for Biological Diversity:
New surveys show a 27-percent drop in the number of breeding burrowing owls in California’s Imperial Valley and provide some of the most striking evidence yet that the species is badly in need of state protections. The Imperial owl population has declined from an estimated 5,600 pairs in the early 1990s to 4,879 pairs in 2007, then dropped sharply to 3,557 pairs in 2008.

“It’s alarming to see such a rapid, single-year drop in owl numbers in an area that is supposed to be a stronghold. Breeding owls been eliminated from a quarter of their former range in California over the past two decades as their habitat has been destroyed and they’ve been shoved aside for urban development,” said Jeff Miller, conservation advocate at the Center for Biological Diversity, which led several groups in petitioning for state Endangered Species Act protection for the owl in 2003. [the petition was rejected].

Burrowing owls in the Imperial Valley nest almost entirely in ground-squirrel burrows along earthen irrigation canals and drains. They represent nearly half the state’s breeding pairs. Once common in California, burrowing owls have been driven out of much of the state, with large populations primarily in areas of intensive agriculture, including parts of the Central Valley, along the lower Colorado River and the Imperial Valley.

It is unknown what is causing the Imperial owl decline, but loss of suitable foraging areas from fallowing of agricultural fields due to water transfers and ground-squirrel eradication programs may play a role. There is no evidence that the Imperial owls are moving elsewhere in California.
Read more here.

The burrowing owl is considered an iconic grasslands species and though it faces many significant threats, there are many people and organizations working to preserve populations throughout North America. In addition to Nature Canada, the other groups who make up the Suffield Coalition are Alberta Wilderness Association, Nature Alberta, World Wildlife Fund Canada, Nature Saskatchewan, and Southern Alberta Group for the Environment.

South of the border, the JournOwl blog stays current with burrowing owl conservation efforts, and the Burrowing Owl Conservation Network actively works on behalf of the species in the States.

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