A study suggests that climate change is affecting the shape of birds’ bodies. To study this, researcher John Soley examined over 2,500 bird specimens from 1950 to 2018 at a variety of locations, observing shifts in birds’ body proportions as they aged. As the birds’ entire body used to be a single bone in each leg, it wasn’t possible to account for the evolutionary evolution of a bird’s leg bone as it adapted to new environments. The team then studied the varying characteristics of different bird groups to identify a key pattern. The picture that emerged is that the activity of muscle in the top part of the leg is increasing with age. This phenomenon is associated with slower flying and an increased need for limb stabilization as the birds age.
The scientists’ analysis suggests that this activity tends to correlate with an increase in temperature as a population ages. This suggests that warm environments, which use more muscle, are preferable for young birds, whereas cold environments, which tend to use less muscle, are preferred for older birds. Since humans are increasingly living in warmer environments, this could lead to a negative impact on bird populations. With human population growth likely to drive global warming, the effects of climate change on the natural world will be significant for all wildlife.