If you're looking for proof of global warming, look out of your window, according to Science News.
A new study by University of Wisconsin-Madison wildlife biologists shows that warm-weather birds aren't flying south for the winter - they are actually spending winter higher north than they did 20 years ago, according to Science News. Benjamin Zuckerberg and Karine Princé looked at information on bird feeder sightings from Project FeederWatch, a site that records data provided by citizens observing their own bird feeders from Dec. 1 to Feb. 8.
"Since 1990, we found that the winter bird community structure has changed, with communities increasingly composed of warm-adapted species," the study says. "This reshuffling of winter bird communities was strongest in southerly latitudes and driven primarily by local increases in abundance and regional patterns of colonization by southerly birds."
Basically, birds aren't flying as far south as they used to, because they don't have to, and bird populations typically seen in the southern part of the United States, like the cardinal and Carolina wren, have been creeping up north. The biologists determined that the temperature range that usually determines where North American birds reside has also been shifting, according to Science News.
"We conclude that a shifting winter climate has provided an opportunity for smaller, southerly distributed species to colonize new regions and promote the formation of unique winter bird assemblages throughout eastern North America," researchers wrote.
