The Farallon Islands are made up of three groups of small islands located nearly 30 miles west of The City. They are home to a unique ecosystem with significant populations of nesting seabirds, marine mammals, and native salamanders, insects, and plants.
However, researchers say the ecosystem is badly out of whack, threatening threatened species. The main threat to the islands is house mice.
Restore the Farallones, a partnership between the U.S. Fish and Wildlife Service and Point Blue Conservation Science, has been restoring the islands’ ecosystem for over 50 years. Wildlife and conservation experts met on Wednesday to discuss next steps to restore the Farallon Islands after the U.S. Fish and Wildlife Service submitted a new application for the project that needs to be approved by the California Coastal Commission . The CCC, which had questions about the project according to an earlier report by the researchers, is expected to discuss the issue at its June meeting.
For years, Point Blue researchers have been the only people allowed to live on the islands. Experts at Wednesday’s meeting, including one of the islanders, Pete Farzybok, Point Blue’s Farallon program manager, spoke about the mice’s impact on native plants and other wildlife, and advocated extinction.
“A one-time use of rodenticide is the only proven solution tested that can safely achieve 100% eradication and restore this important ecological site,” said Zach Warnow, Director of Communications, Point Blue.
Warzybok said the mice prefer to eat native plant species over invasive plant species and spread the seeds of invasive plant species, changing the island’s vegetation. He also said they are falling prey to the invertebrate population and are competing for resources with native salamanders. They also consume salamanders and salamander eggs.
In addition, the mice attract burrowing owls. Although the owls are a natural part of the ecosystem, they usually migrate. But the number of mice they have available to feed is an incentive for them to stay, Warzybok said. This causes them to hunt a species of bird called petrels.
“Unfortunately, what happens in winter, when it starts raining and getting colder, the mice experience a seasonal decline and their mouse population crashes, leaving the owls left without much food,” Warzybok said. “At this point they have to switch to something else and start catching petrels.”
If nothing is done, petrel populations are projected to decline by 60% over the next 20 years, which is significant, Warzybok said, Given that the islands are home to half of the world’s petrel population.
According to Warzybok, removing mice will help “buffer the Farallon ecosystem against the effects of climate change, warming and air temperatures [and] changing precipitation patterns. “
“By eliminating the effects caused by the mice, we are giving the entire Farallon ecosystem a greater ability to withstand these changes and adapt to long-term climate impacts,” Warzybok said.
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