Changes in bird population are signs of climate change

Fresno Bee Editorial

Tuesday, Feb. 24, 2009

A wave of the binoculars to citizen scientists. The field observers and feeder watchers who participate in the National Audubon Society's annual Christmas Bird Count have provided base line information for studies that challenge us to deal with ecological disruption.

Using bird counters' data collected during the past 40 years, scientists say bird migrations clearly are changing, with the most likely explanation being global warming.

Over those decades, average January temperatures rose in the lower 48 states by 5 degrees Fahrenheit, and birds seemed to be wintering farther north.

Audubon's study confirms the reports: 58% of the observed species -- 177 of 305 -- showed significant movement northward. Bird species also moved inland from warm coastal areas.

In a separate study using computer modeling and bird counters' data, Audubon California's scientists William Monahan and Gary Langham projected effects on birds from low, moderate and high greenhouse gas emissions.

"On average, California's landscapes will lose 6% of their bird species under low emissions, 14% under moderate emissions and 19% under high emissions," they wrote.

From the Swainson's hawk to the yellow-billed magpie, the scientists pinpoint how species and regions would fare.

The "hot spots of loss" in the south include areas of the Mojave and Sonora deserts, Coast Range, eastern Sierra Nevada and Central Valley. In the north, the Modoc Plateau and portions of the Cascade and Coast Range would suffer the most severe losses under the high emissions scenario.

Why should anyone care if birds range northward or disappear? As the health of the birds goes, Langham says, so does the health of the habitat.

What is the best course of action? Cut greenhouse gas emissions, target areas for conservation and move toward clean energy.

Protecting bird habitat, after all, is protecting our own quality of life.