Mountain birds climb with increasing temperatures – ‘We call it an escalator to extinction, as the birds are going up until they run out of room’

By ANNA JOHNSON
5 March 2014

(Cornell Daily Sun) – Recent research has found that as tropical temperatures climb as a result of climate change, mountain-dwelling tropical birds are doing the same. While climate change is not a new concept, the study conducted in Papua New Guinea aimed to examine the virtually unexplored question of climate change’s effects on birds, according to Benjamin Freeman grad and Alexandra Class Freeman, a staff researcher at the Cornell Lab of Ornithology. “Climate change has a big impact on today’s world and there’s a problem in that nobody had really measured how climate change is impacting tropical birds,” Freeman said. “In our studies, we read about field work that Jared Diamond had done in the 1960s, and we realized that would give us an opportunity to go back to the same places, observe where birds live now and compare that to the historical baselines.” Using 47 years of data previous research created a launching pad for a local study with wide applications, according to Class Freeman. “In the present, these [data] are valuable. [We] got permission to work on this mountain to study climate change effects in the tropics to see whether diversity has changed,” Class Freeman said. “This ties a globally ambiguous symptom of greenhouse gas use to a real-world effects evident in bird species ranges on a spectacularly isolated mountaintop.” After months of collecting data, the researchers found strong support for the existence of this trend of the birds’ ascent. Birds have shifted both the upper and lower elevation boundaries of their preferred habitats, Freeman said. The impending effects of this trend could be lethal for birds, according to Class Freeman, who said it can only continue for so long before the population exceeds carrying capacity. Carrying capacity is the maximum number of members of a species that a habitat can support. “Bird species living at the top are stuck, with no place to go, leading to their probable extinction if climate trends continue similarly,” Class Freeman said. “Mountains are cone-shaped, thus populations are much denser at the top — there is a sharing of smaller space by all species that inhabit mountaintops currently and those moving upslope. … This demonstrates that slight changes in climate can cause large changes in behavior.” The particular lifestyle needs of these tropical birds make for an even grimmer picture when faced with relocation, according to Freeman. “These are very different from our Ithaca birds that happily fly from Ithaca College to Cornell,” Freeman said. “These are birds that are born in a small patch of woods. … If they’re lucky enough to survive, they stay in one patch their whole lives.” “[We call it an] escalator to extinction [that the birds are] going up until they run out of room. … If they’re the losers, the escalator is running quickly,” Freeman said. “Or, it’s king of the hill. … We don’t know which is the more correct scenario, [so] we’re going to do some experiments in the Adirondacks.” [more]

Researchers Find That Mountain Birds Climb With Increasing Temperatures