As if scientists needed any further proof of global warming, zoologists have spotted a new trend in the migration pattern of many birds, suggesting that the birds are altering their migratory habits to spend their winters further north than ever before. As the average temperatures in the US have increased over the past decades, many migratory birds, such as the Finch, have been altering their winter migration. In fact, the Finch now migrates 400 miles north of its previous winter home.

The American Audubon Society has released a research study which concluded that over 150 species of birds throughout North America have shifted their migration further North. Birds such as Robins, Finches, Seagulls, and even Owls are now wintering further north than ever before.

Of course, there are many factors that can affect bird migration patterns, including deforestation, pollution, and our urban sprawl. However, researchers for the Audubon Society that global warming is the only logical way to explain how so many different species of birds have moved their migration patterns northward.

The Audubon Society study took a look at bird migration statistics and weather patterns over a 40 year period. They determined that average temperatures have jumped significantly, climbing approximately 5° on average during the month of January. The northern United States has seen the most pronounced “warming” and as a result, many species of birds from northern areas are staying closer to home in the winter.

However, the study’s findings were not news at all too many dedicated birdwatchers, who have noticed for decades that birds of all types have been shifting their migrations further north. Similar studies conducted in the United Kingdom also suggest that bird migration is changing rapidly.

Not all species are moving further north, however. And scientists remain baffled why some species have shifted their migration by as much as 400 miles — while others seemingly haven’t budged an inch. The recent Audubon Society study suggests that as many as half of North American bird species have altered their migration pattern further north.

Some birds, such as the Carolina Wren, have drastically altered their migration, and are now more common in the northeastern United States than they are in the Carolinas (the very area they were named after). Birdwatchers in the Carolinas have noted that the Carolina Wren is now rarely spotted in the area, while they appear to be plentiful in Maine and throughout New England.

Researchers say the evidence is overwhelming, and the obvious shift in bird migration patterns is proof positive that global warming is both real and increasing.