PRBO Conservation Science
Quarterly Journal of PRBO Conservation Science, Number 159, Winter 2010: Extreme Weather


With the long-term Farallon monitoring program, we can put future observations into the context of decades of baseline data.

Weathering Extremes on the Farallones

Russ Bradley

Extreme Weather—and Birds
CEO's Column: Weather or Not?
Sagebrush Snowstorm
Weathering Extremes on the Farallones
Desert Birds and Drought
Marsh Birds Time the Tides
Tipping Points for Penguins
Recording the Weather
Journal Excerpts
El Niño, Winds, and Upwelling
Focus on Extreme Weather
Planned Giving Checklist
PRBO Highlights
Funders, Skippers, Staff

Gigantic waves pound East Landing. Photo by Pete Warzybok.
Extreme weather is one of the elements that makes the Farallon National Wildlife Refuge such a rugged and formidable environment—ideal for an isolated colony of thousands of seabirds and marine mammals. However, extremes of wind, waves, sun, and rain can have severe impacts on the islands' wildlife populations.

Animals using the island as a resting and breeding site all cope with wind, which is part of life on the Farallones. However, extreme winds not only prevent biologists from moving around the island: they can change the attendance patterns of seabirds and, especially if they occur before birds are incubating, can literally blow away nests of species like cormorants.

A Western Gull changes shape during exceptional gale winds on Southeast Farallon Island. Photo by Caitlin Kroeger.
Extreme waves can also have severe effects. Our main elephant seal study area, a colony called Sand Flat, ironically has practically no sand at all. This formerly sandy beach (the preferred kind of habitat for elephant seals on land) washed away during the El Niño winter of 1983—along with several elephant seal pups.1

While researchers on the island often welcome the sun's heat, most wildlife there does not: these are species adapted to much cooler conditions. A May heat wave in 2008 stressed Cassin's Auklets that were incubating eggs in nest boxes used by PRBO for monitoring this burrow-dwelling seabird (we took unprecedented measures to cool and protect those several hundred nests; see page 8). Heat may also have contributed to Brandt's Cormorants and other species abandoning their nesting efforts and decreasing their attendance at the island that year.

Exceptional rainfall on the Farallones, while a great benefit to our water collection efforts, can also cause problems for wildlife. In 2005, anomalous southerly atmospheric flow in May brought storms and heavy rains during the seabird breeding season. This left natural auklet burrows in the ground full of standing water, and we observed a few gulls' eggs floating away from their nests into newly formed pools.

Throughout PRBO's 40 years of continuous research, monitoring, and stewardship on the Farallones, in partnership with U.S. Fish and Wildlife Service, we have seen a range of severe weather effects on seabirds and marine mammals. With the frequency and impact of such events potentially increasing, there is all the more reason to continue our efforts. With this invaluable long-term monitoring program, we can put future observations into the context of decades of baseline data.

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