In the most untouched, pristine parts of the Amazon, birds are dying. Scientists may finally know why | Birds

SSomething was happening to birds in Tiputini. The Center for Biological Diversity Research, which was buried deep in the Ecuadorian Amazon, was always distinctive. It is amazingly far: a small prose from the search cabin in 1.7 meters (4.2 meters) of virgin forests. For scientists, it comes as soon as possible to monitor wildlife in the rainforest in a world that has not touched the human industry.

Almost every year since his arrival in 2000, Environmental world John Ji Blake There was birds to calculate. He rises in front of the sun, he recorded the density and diversity of the Fajr choir. Slowly walking the perimeter of conspiracies, and pointed to all the types he saw. To blame one year, he and other researchers were throwing huge “fog” networks that caught birds in their woven, where they would be calculated, unjust and released.

For years, these charges have acquired annual bird fluctuations; They had good and bad years, and the seasons were broken by storms and others when they flourished. But by 2012, Blake and his collaborators could see something that was turning. Birds were dying: not at the masses at the same time, and the plague hit them, but a generation according to the generation. The annual fluctuations he spent for a decade stopped slowing up ascending leaps, as the trend line turns into an indivisible slope. By 2022, their numbers decreased to nearly half. Blake did not need the graph to tell him that something was wrong; When he got up to listen to the dawn choir, he heard that he was silent. The songs were missing. Some species simply disappeared.

He says, “A number of them have not heard a few years ago.” Away from the outside world, it has intermittent power and depends on satellite contact. “There is definitely some species that, for any reason, does not seem to be here anymore.”

In North America and Europe, scientists have warned the numbers of birds for a long time, but this was often explained by their communication with humans. With the expansion of cities and farms, forests around them become fragments, shrinking animal habitats, pollution with rivers, pesticides and fertilizers kill insects. Even pets are a factor – in the United States, kill household cats 4 billion birds general. However, Tiputini is one of the few planet stains that do not feel directly these pressures: there are no farms near, no polluted factories, no records exceeding, and no ways.

In other distant sites around the world, scientists have begun to notice similar trends. In Brazil Biological dynamics of the forest fragments project (BDFFP) is an environmental study located in the depth of the primary Amazon forest, which cannot be accessed by the road. These areas carry some of the oldest living forests on this planet – they evaded the events of the ice age that restores forests in the United States and Europe with the growth and decline in ice rivers. “In the Amazon, we had pockets of stable forests over millions of years,” says environment scientist Jared Wolf, a research scientist at the project. “The site is really amazing.”

But in 2020, when the researchers compared the numbers of birds with the eighties, they found a number of species A deep decrease. In another location in Panama, scientists work in an extension of 22,000 hectares (54,000 acres) of sound forests He was collecting bird data Since the mid -seventies. By 2020, their numbers were out of the shelf: 70 % of the species decreased, most of which were severe; 88 % lost more than half of their population. In some sites, scientists began monitoring the “collapse of a complete community,” says Wolf. “This happens in virgin environments, which is really annoying.”

For decades, scientists were trying to understand what was going on. Blake and collaborator with Ornithology Bette A Loiselle published the first paper to document the decreases in 2015, but he could not say permanently what causes them. Test the birds for diseases and parasites, and they did not find any clear links. They considered the possibility that an unknown or contaminated toxin leaked – but there was no evidence of this. “I think everything that causes these declines is more widespread,” says Blake. “It will not be a special thing in the Tiputini.”

They concluded that the most likely answer is the climate crisis. “There is only very little – at least I know – has great effects around the world,” says Blake.

After a decade, their instincts are proven correct. This week, Wolf and the collaborators have published a new work that directly connects the increasing temperatures to birds’ declines. Their research, Posted in Science AdvancesThe comic birds that live in the forest in BDFFP against detailed climate data. They found that the harsh dry seasons were greatly reduced from the survival of 83 % of the species. Increase 1c at the temperature of the dry season would reduce the average bird survival by 63 %.

How to cause the heat that causes the numbers of birds is difficult to determine, but “these birds are fundamentally related to small small changes in temperature and precipitation.” One of the most urgent ways that the heating planet is harmful to wildlife by placing it outside the step of their nutritional sources: when a smaller number is engraved. Their nests begin to fail. Within a few generations, their numbers decrease.

The losses documented in these distant stations have traces that exceed the birds. “The idea has always been that if you have huge spaces of forests, it will protect everything,” says Blake. “Well, it protects a lot of things. But it seems not everything.”

Most western conservation works by dividing the wilderness, as parks or national reserves. These places like Arks: wildlife tanks that we hope will be rescued, even when people turn the earth around them. But what researchers saw with the birds suggested that these corners are much more fragile than he thought.

Wolf is similar to the problem of pollution in a large body of water. When scientists measure water quality, they consider pollution in two ways. The pollution of the “point source” may be a flowing oil tube: it causes severe damage, but by turning it off in solving the problem. The “unspecified source” will be the small drops of the oil coming from each car in the region, and washed it from roads and to the waterways: every small contribution may be, but the cumulative effect may be huge – and it is difficult to stop it. “It is very difficult to fight,” says Wolf. What is happening to birds “seems to be a source without points; an evil complicated problem as you have collapses in biological reactions that cause this decrease.”

But realizing what is happening is necessary to develop solutions, Wolf says. “There is one thing that has become particularly tired as a professional researcher, which is to write these deaths for birds,” he says. Searching for virgin areas can also reveal possible solutions: early data indicates that some forests deceive declines. Determining the cause – and protecting them – is very important.

For scientists who see birds disappear, there is sadness in watching some of the most beautiful environmentally rich places in the world. “It is frustrating,” says Blake. “When we got here and started searching, we were completely surprised by the number and diversity of birds. We continue to do the work – but it is difficult to be excited to do this because there is very little.”

Find more Covering the era of extinction hereHe followed the correspondence of biological diversity Vepi Weston and Patrick Greenfield In the Guardian app for more nature coverage.