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Forty Years of Data at Two PRBO Field Stations

Recording the Weather

Nat Seavy, PhD

Long-term weather records at PRBO field stations are critical to our understanding of how weather events and trends affect the birds and ecological systems that we work to study and protect.

At PRBO's Palomarin Field Station, collecting weather data is literally like clockwork: an alarm sounds at 8 AM, 12 PM, and 4 PM each day of the year. One of our resident interns then reads the current temperature, wind speed and direction, and barometric pressure from computerized instruments and, walking outside, records the visibility and cloud cover and checks the rain gauge. With a few technical upgrades, this weather protocol has been followed constantly since the 1970s.
PRBO intern Matt Barbour carries out the daily routine of recording sea-surface temperature at Southeast Farallon Island, adding to a data set begun in1925. Photo by Annie Schmidt.

Twenty miles offshore, PRBO biologists gather much of the same information at the Farallon Islands. "In addition, we record information about ocean conditions, such as swell height and period and sea surface temperature," explains Russ Bradley, Farallon Island Project Manager. To measure sea surface temperature, a field biologist stands at the rocky shore, throws a bucket on a line into the surf, and hauls in a water sample. Says Russ, "This was begun by the U.S. Coast Guard in 1925, so it represents the longest-running data set that PRBO maintains."

PRBO biologists use data such as these to develop detailed understanding of how weather influences the birds and other organisms we study.

· At Palomarin, U.C. Davis graduate student Kristy Dybala is using annual weather to understand year-to-year differences in the survival of Song Sparrows.

· In the Central Valley, wetland biologist Khara Strum is collecting rainfall data in order to understand changes in shorebird habitat availability.

· At Cosumnes River, also in the Central Valley, senior scientist Chrissy Howell, PhD, has headed a PRBO analysis of the rainfall patterns that determine success for riparian restoration projects, using Song Sparrow breeding success as a gauge.

· On the Farallon Islands, biologist Derek Lee has discovered that the proportion of male and female elephant seal pups born each winter changes in correlation with El Niño phases.

Other scientists also make use of the weather records collected by PRBO.

· The National Oceanographic and Atmospheric Administration incorporates Farallon weather observations into ocean forecasts for mariners, and may also use them in climate models that project future conditions.

· Wayne Sousa, U.C. Berkeley professor, uses rainfall data from Palomarin in his study of population dynamics of a salt-marsh snail at nearby Bolinas Lagoon.

As we enter an era of rapid climate change, weather observations become increasingly important. Historical records will help us understand what to expect as we encounter new conditions and more frequent extreme events. Continually monitoring into the future will help us track our climate's trajectory.