Over the past 40 years, observations have shown that more than half the birds seen in North America during the first weeks of winter have moved dramatically northward, toward colder latitudes, as shown by another study released this week by the National Audubon Society. For some species of birds that translates into an average of 35 miles; however, for more than 60 of them, the distance turned out to be 100 miles.

 

Is climate change causing bird movements? While causation is nearly impossible to prove, global climate change is by far the most probable explanation, the study writes. Indeed, the movements are consistent with birds’ biological needs. This report can be found here (PDF).

 

The two studies combine findings perfectly, stating out the obvious trend for birds in North America in general, and California in particular: climate change is causing a shifting landscape, challenging the equilibrium of delicate ecosystems, and threatening species of wildlife with extinction.

 

California researchers at Audubon focused their study on 312 common coastal and terrestrial bird species in the region. With the help of a geographic information system (GIS), they attempted to map the areas and habitats that continue to remain important to birds in California, but also the movement corridors for these birds, the areas where the species are doomed to extirpation, as well as the areas where the birds would benefit from habitat restoration, or areas where assisted migration will be needed in order to ensure the survival of the species.

 

The models obtained by the California researchers highlight once more the importance of reducing greenhouse gas emissions and working toward ensuring conservation for species of wildlife here. According to their estimations, California’s landscapes could lose 6 percent of their bird species under low emissions, 14 percent under moderate emissions, and 19 percent under high emissions.

 

However, some areas will be more affected than others, such as parts of the Mojave and Sonora deserts, Coast Ranges, Eastern Sierra Nevada, and Central Valley. In northern California, the study also warned about significant losses across Modoc Plateau, but also portions of the Cascade and Coast Ranges.

 

To give a more specific example of how important climate change mitigation is, the study revealed that the California Gnatcatcher is in danger of losing more than half its habitat, or as little as 7 percent if the problem of climate change is well addressed, the Chestnut-backed Chickadee could lose 49 percent of its habitat, or just 16 percent if climate change is well addressed, while the Yellow-billed Magpie -- a bird that only lives in California’s central Valley and Coast Ranges -- could lose 75 of its habitat, or just 9 percent if climate change is well addressed.

 

For years, people have made considerable conservation investments with their fingers crossed that their work won’t simply be erased by climate change in a few years. Having a sense of what the landscape actually will look like 50 or even 100 years into the future will allow us to make much better conservation investments today -- Bill Monahan, senior GIS scientist at Audubon California.

 

The study draws attention on the challenges and the pressure posed by climate change on California’s ecosystems, in addition to promoting climate change mitigation through a bill called the California Global Warming Solutions Act. The detailed report can be found here (PDF).