A new study shows that birds are shrinking, and their wingspans are actually growing, and it’s all because the climate warms. Researchers analyzed more than 70.000 specimens from about 52 North American migratory bird species, which were collected in nearly 40 years. These birds died after crashing into buildings in Chicago, Illinois.
The authors of the study stated that it is the most extensive study of this kind and that these findings are essential for us – they help us in understanding how animals actually adapt to climate change. The study found that almost all the species were getting smaller. This comes from the lead author of the study, Brian Weeks, who is an assistant professor at the University of Michigan.
The species were diverse, but they all responded in a similar way. The fact that it was consisting was shocking.
This kind of studies – of animals responding to climate change – usually focus on shifts in the geographical range, or the timing of certain events, such as birth or migration. However, this study suggests that body morphology is also essential. It’s quite hard to understand how species will actually adapt to these three aspects.
From 1978 to 2016, the length of the lower leg bone of the birds shortened by 2.4%. At the same time, the wings grew by 1.3%. Pieces of evidence show that warming temperatures were the reason behind the decrease in body size, which also caused an increase in wing length.
Mr. Weeks stated that migration is a difficult thing that they do. He explained that the smaller body size is equal to less energy available for the birds to complete their journeys, which sometimes are long. Those birds that survived the migration were the ones with longer wingspans.