Scientists Say Billions of Birds are Changing Migration Habits

The world’s birds are already finding their own ways to adapt to the effects of climate change. In addition to migrating at different times to newly hospitable locations, they may also shorten their migrations, using their energy on eating and breeding, rather than on flying.

Miguel Ferrer, an ornithologist at Spain’s Doñana National Park, told a recent gathering of about 200 scientists that about 70 percent of the world’s migrating birds, 20 billion in total, have changed their migration habits over the past few decades. Some birds have stopped migrating altogether.

“Long-distance migrators are traveling shorter distances; shorter-distance migrators are becoming sedentary,” Ferrer said. “That has a knock-on effect on almost everything they do, from breeding habits to feeding habits to their genetic diversity, which in turn affects other organisms in their food chain. It’s a huge behavioral change, forced on them by rising temperatures.”

The biggest reason behind this behavioral shift is climate change.

“Climate change and environmental change are simultaneously forcing migratory birds to adapt extremely quickly”, says Ian Newton, a Royal Society member and longtime researcher.

The adaptation process was necessary during the Ice Age, when species needed to change habits in order to adapt to a changing climate. However, if this adaptation process is needed much faster than previously, the process may be no where near as successful.

“Average annual temperatures are moving northward at a rate of four kilometers (about 2 miles) a year,” Mr Ferrer estimates, “so the normal summer temperature in your city 12 months ago is now normal four kilometers further north. It doesn’t sound like a lot, but that’s 20 times quicker than temperatures changed in the last Ice Age. At the same time, because birds are migrating less, one traditional path for genetic development, when they strayed from their migration paths by accident and had to adapt, is being closed off.”