A new study suggests that the last ice age may have caused a major disruption in bird migration, with some species losing the ability to fly long distances.

The study, published in the journal Nature Ecology & Evolution, found that many bird species that currently migrate long distances evolved this behavior relatively recently, after the last ice age ended about 10,000 years ago.

This suggests that the ice age may have prevented some bird species from migrating long distances, and that these species only evolved the ability to migrate after the ice age ended.

The researchers studied the DNA of 212 bird species, including both long-distance migrants and non-migrants. They found that the long-distance migrants evolved from non-migratory ancestors relatively recently, on average about 1.8 million years ago.

This is much more recent than the evolution of bird migration in general, which is thought to have originated about 100 million years ago.

The researchers say that the ice age may have caused a major disruption in bird migration, with some species losing the ability to fly long distances. This would have forced these species to adapt to living in a smaller area, and may have led to the evolution of new bird species.

After the ice age ended, the climate warmed and the glaciers melted, creating new opportunities for bird migration. This may have led to the re-evolution of long-distance migration in some bird species, and the evolution of new bird species that were adapted to long-distance migration.

The researchers say that their findings provide new insights into the evolution of bird migration, and help to explain why some bird species migrate long distances while others do not.

They also say that their findings have implications for the conservation of migratory birds, as climate change could disrupt bird migration patterns and threaten the survival of migratory bird species.