A careful reformulation of a three-decade-old bird study on a mountain slope in Peru gave scientists a rare opportunity to demonstrate how the changing climate is driving species from the places they best adapt to.  Surveys of more than 400 species of birds in 1985 and then in 2017 have revealed that populations of almost all have declined, eight of them had completely disappeared, and almost all had moved to higher levels, something by the scientists is called "escalator to extinction". "
" Once you've moved up as far as possible, there's nothing left, "said John W. Fitzpatrick, one of the authors of the study and director of the Cornell Laboratory of Ornithology.
"On This Mountain Some populations of ridgetop bird species have been literally wiped out.
It is not certain that the birds have been displaced due to temperature fluctuations or indirect influences, such as shifts in the insect areas or seeds from which they feed.
The results of the study published in the trial of the National Academy of Sciences confirm what biologists had long suspected, but few occasions had to confirm.  A study of birds on the same mountain in 1985 provided scientists with a rare and useful foundation.
Previous research has documented habitats of birds and other species that are advancing in response to warming temperatures at high altitudes or latitudes. Mark Urban, director of the Center of Biological Risk at the University of Connecticut, who was not involved in the study, said:
"A study like this, where you have historical data that you can refer to, is very rare , "Urban said," As long as the species can spread, you will see species marching up the mountain until this escalator becomes a staircase to the sky. "
In 1985, Fitzpatrick set up a base camp next to a river on a mountainside to the southeast His goal was to catalog the habitats of the tropical bird species that lived there, and his team spent several weeks walking up and down the Cerro de Pantiacolla, using fine nets known as fog nets to trap and release birds Journals of birds caught, spotted or twittered in the woods.
Two years ago Fitzpatrick submitted his journals, photos, and other materials to Benjamin Freeman, a postdoctoral fellow at the University of British Columbia's Biodiversity Research Center has been researching tropical birds for more than a decade, the journey began in August and September 2017. With old photos of mountain panoramas, his team found the same base camp.
Freeman has largely recreated Fitzpatrick's path and methodology to see what had happened in the intervening years, a time when the average average temperatures on the mountain rose 0.42 degrees Celsius. Because the mountain is located on the edge of a national park, the area had not been disturbed.
In addition to the 12-meter fog nets on the slopes, Freeman's team set up 20 microphone boxes on the mountain
"We found that the bird communities moved up the slope to reach the climatic conditions to which they originally adapted were the main author of the study, Freeman
Near the top of the mountain, the bird species moved on average 98 meters higher.
"We think the temperature is the main switch to explain why the species live where they live on mountain slopes. Freeman said. "A large majority of the species in our study did the same."
Birds that stick to tight temperature ranges – in regions without large seasonal fluctuations – may be particularly vulnerable to climate change, Fitzpatrick said. "We should expect that what is happening on this mountain peak is more general in the Andes and other tropical mountain ranges," he said.