Climate change affects the natural world in many and myriad ways, Chris says we only know about the most apparent ways.

The annual Christmas Bird Count just came to a close. It's the oldest, largest wildlife survey in the world, and New Hampshire plays its part. Each year at this time, volunteers go forth to tally every bird they see in 21 designated areas around the state. Whether in New Hampshire or Antarctica, a count takes place in 24-hour period at any point from December 14 through January 5th.

Last year's results confirm a record number of overwintering robins in New Hampshire. A lot of people were surprised by the sight of robins against a backdrop of snow. Each winter predictably delivers a few Canadian species that descend this way because of food shortages up north. Last year Pine Siskins showed up in a lot of states in record numbers. This won't surprise anyone with backyard birdfeeders that were positively mobbed by these lively, small finches.

As for long-term trends, climate change is being watched and analyzed with care. Over a 40-year study period average January temperatures in the U.S. increased significantly: by four and a half degrees. This was matched by a shift in bird distribution. Southern species are moving north; and northern species that head south for the winter aren't going as far.

Birds are by far the easiest wildlife species to study. They're visible, they’re vocal, they have a legion of loyal observers – 47,000 observers in last year's Christmas Bird Count in the United States. Survey data indicates that birds are adaptable to short-term temperature changes, shifting their range in response.

It's not so easy to determine how other wildlife – as well as plant – species are responding to those changes. This presents some pretty big questions about plants and animals that aren't as mobile.

Script by Francie Von Mertens