Amazon birds have dwarfed to adapt to climate change

In the last forty years, the climate change man-induced has not only reduced the number of birds in the jungle amazonian, but also has changed their size: they have become smaller and with longer wings.

This is warned by a study, published this Friday in Science Advances, which explains that these physical changes, which have occurred over several generations, have helped birds adapt to the increasingly hot and dry conditions of the season. dry (from June to November).

“Even in the middle of the pristine Amazon rainforest, we are seeing the global effects of human-caused climate change,” warns Vitek Jirinec, an ecologist at Louisiana State University (LSU) and lead author of the study (the first to discover changes in the size and shape of the bodies of non-migratory birds).

To do the study, the authors analyzed data from more than 15,000 birds captured, measured, weighed, tagged, and released in the Amazon in the last 40 years.

The data showed that, since the 1980s, almost all bird bodies have reduced in mass or become lighter and that most species have lost an average of 2% of their body weight each decade. For a species that weighed about 30 grams in the 1980s, the population now weighs an average of 27.6 grams.

In addition, the data were collected over a wide area of ​​the rainforest, showing that bird changes are not limited to a specific site, but rather a “significant and widespread” phenomenon that probably not only affects birds.

“If you look out your window and think about what you are seeing, you will see that the conditions are not those of 40 years ago and it is very likely that plants and animals are responding to these changes”, reasons Philip Stouffer, researcher at LSU and co-author of the study.

Scientists investigated 77 species of rainforest birds that live from the cool, dark jungle floor to the warmer, sunnier forest and found that those that reside higher in the understory and are more exposed to heat and sunlight. drier conditions, they presented more drastic changes in weight and wings.

The authors believe that birds have adapted to a warmer and drier climate by reducing the load on their wings (weight) and lengthening their length to be more energy efficient in flight. It is their way of adapting to climate change, but will they be able to cope with an increasingly hot and dry environment? That question remains unanswered, the authors conclude.