Seabirds: ‘Climate change is here’

Magellanic penguins on the Patagonian coast

To convince naysayers that climate change is real, maybe all we need to tell them is to look up in the sky – or down into the ocean.  Two recent studies show that seabirds can be important sentinels of a changing climate.

Says Dee Boersma, University of Washington ecologist and one of the world’s penguin experts, in a NY Times article today:

“The big thing is that penguins are showing us that climate change has already happened. The birds are trying to adapt. But evolution is not fast enough to allow them to do that, over the long term.”

Boersma has been traveling to Argentina since 1982, surveying and studying the Magellanic penguins that call the country’s southern coasts their home.  Her recent research in Ecological Monographs showed that although the penguins live in protected areas, climate change and fisheries practices have left the birds with little food. They need to travel up to 25 miles farther now to find food, she says, which depletes their energy reserves and leaves their mates starving while sitting on  their eggs.

When seabirds can’t get consistent food, it can throw off other behaviors, some of which are critical. Changes in ocean productivity are linked to climatic factors such as wind, temperature and seasonality. The Cassin’s Auklet, which occupies coastal waters from Alaska to Mexico, relies heavily on seasonal ocean upwellings to produce enough planktonic food to sustain its breeding behaviors. Shaye Wolf of the Center for Biological Diversity, reporting in the journal Ecology, found that when these upwellings are disrupted, likely because of the changes in surface winds and sea currents associated with climate change, the birds breed later and have a lower chance of leaving successful offspring.

As Wolf puts it, the terrestrial habitats these birds use are often “underappreciated, understudied and underprotected.”  But even if we appreciate, study and protect the birds’ nesting grounds, these studies suggest that an increasingly warm ocean will continue to erode seabird populations.

Boersma, P., Rebstock, G., Frere, E., & Moore, S. (2009). Following the fish: penguins and productivity in the South Atlantic Ecological Monographs, 79 (1), 59-76 DOI: 10.1890/06-0419.1

Wolf, S., Sydeman, W., Hipfner, J., Abraham, C., Tershy, B., & Croll, D. (2009). Range-wide reproductive consequences of ocean climate variability for the seabird Cassin’s Auklet Ecology, 90 (3), 742-753 DOI: 10.1890/07-1267.1