We know that climate change has multiple impacts on birds: changes in the distribution of species and in the composition of the community itself, alteration of demographic parameters (both in survival and reproduction), or even changes in the periods migration and laying dates.
Migratory species must adapt their seasonal movements to the availability of food resources, which varies with temperature and the level of rainfall. Under the temperate and boreal latitudes, for example, the average dates for the return of migratory birds (spring migration), advanced by an average of two days per decade in the last half of the 20th century.
A few years ago an indicator of the impact of climate change on bird populations was developed, using an index based on the relationship between the populations of species that are predicted to be favorably influenced by warming, and likely to expand their distribution area, while taking into account those species that it predicts will be damaged, and for which a contraction of the area is expected.
This made it possible to discover that, on a European scale, the value of the index has increased considerably since 1980, which would suggest a growing impact of climate change on different bird populations .
In this sense, according to a new study, climate change is affecting the treasure of biodiversity in the Amazon . And it seems that dozens of birds would show that changing weather would actually be shrinking their bodies and lengthening their wings.
According to the study authors, “Our findings show that man-made climate change, and thus the individual lifestyles of people around the world, is manifested in something as fundamental as the size and shape of the planet. body of birds in the intact Amazon rainforest ”. In other words, “these results highlight the global part of climate change.”
The study has been published in the journal Science , and analyzes how 77 species of Amazonian birds have evolved over the last four decades. As scientists discovered, birds are effective indicators of different environmental changes .
In the case of mammals, for example, they tend to have nocturnal habits and generally live sheltered (for example, in burrows). Birds, on the other hand, are always exposed to the elements, to which it would be added that they are relatively easy to observe and measure.
In Manaus, the capital of the state of Amazonas, the researchers collected as much data as they could on each bird. For example, they measured over 11,000 and weighed about 15,000, assessed their age, and labeled them before returning them to the same 4,100-hectare area of preserved rainforest.
Thus, armed with the newly collected data, and historical records obtained over the past 40 years, the researchers set to work analyzing the 77 species of non-migratory birds that live in the understory of the forest.
What was one of your key findings? On average, the muscle mass of all the species they analyzed had decreased since 1980 . And, in addition, 36 of them had lost about 2% of their body weight, per decade. At the same time, 61 of the 77 species saw an increase in wing length .
On the other hand, the study also established the relationship between body mass and wing length, in order to verify the general changes that had occurred in the morphology of the birds and their ability to fly.
They found that longer wings, on lighter bodies, would help expend less energy when flying . In this way, they concluded that changes in the climate are responsible for the physical changes in the birds’ bodies .
