While in some cases, climate change is causing animals to locate to new places, it’s mostly regular migration: Every fall, tiny hummingbirds face high winds and bad weather to migrate from Canada and the northern United States to as far south as Mexico, then back again in the spring–an amazing total of 4,000 to 5,000 miles. But migrations like this may be even more rare in the future.
In the December 20th edition of the New York Times, Jim Robbins quotes conservationist Keith Aune as saying, "Long-distance migrations as a whole are rapidly disappearing." But they’re essential: According to Aune, "They are about survival. When we block migrations, we lose the ability to sustain a population."
Robbins writes: "Wildlife migrate to seek water or food at different times of the year, or to breed. The ability to freely move across the landscape could become even more important as the climate changes and wildlife need to adapt–following the movement of the plants that they eat or looking for new sources of water as old sources dry up." (NOTE: You can still get a copy of "Superstorm" from the Whitley Strieber Collection, and it will come with an autographed bookplate designed by Whitley!)
Most of these migrations take place in the US, and the longest one is the 400 miles traveled by some Alaskan caribou. Migratory species that no longer exist include the huge herds of bison that once moved across the Great Plains. While they still exist, their numbers have now dwindled to a few preserves.
There was also the passenger pigeon, which is now extinct, but 150 years ago, according to Robbins, a migrating flock of them was so large that "it took 14 hours to pass one spot in Ontario."
The number of migratory songbirds is down across the US. In the spring, these birds eat 3,000 to 10,000 TONS of insects each day as they travel. Robbins quotes wildlife expert David Wilcove as saying, "It’s a legitimate concern. Presumably with the decline of songbirds, insect damage to crops and forests could be worse."