"Staircase To Extinction" For Mountain Bird Species Pushed Upslope By Warming World
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According to Freeman, this trickle-down effect of global climate change spells disaster for an increasing population of birds in a decreasing area of suitable habitat.
“A couple species that we studied that live on the mountaintop and are likely to go locally extinct are [the] Crested Berrypecker and Crested Satinbird,” Freeman said. “Even if a species persists … there’s less land area, and smaller populations will be supported for each species. … We think mountain extinctions are going to happen.”
The researchers themselves said they were surprised at the extent of the trend. “We didn’t know really what to expect,” Freeman said. “It was surprising to me that so many species were moving up slope so strongly.” Class Freeman said the uniformity of the trend at a variety of elevations was especially surprising.
“Lower elevation birds were moving up at about the same rate as upper, [which is] surprising mainly because you might expect some species to just expand if they could tolerate all temperatures — which we suspect they can,” Class Freeman said. “Species might be engaged in complex competition for habitat and food as they are squeezed into a smaller area at the top of a mountain.” This complex interaction between species does not exclude humans, and according to Freeman tropical birds are not the only ones feeling the effects.
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http://cornellsun.com/blog/2014/03/05/researchers-find-that-mountain-birds-climb-with-increasing-temperatures/