Bird migration may have been common during last Ice Age

Migration across the seas may have been as important for birds during the last ice age — when much of the planet was covered with snow and ice — as it is today, according to a study which reconstructed bird movement patterns over the past 50,000 years. The study noted that many bird species migrate in response to seasonal variations in climate, and this phenomenon could be older than previously thought.

This behaviour can be flexible with some species already having altered their routes to cope with ongoing climate change, the researchers, including Marius Somveille from the Max Planck Institute of Animal Behaviour in Germany, said.

They added that until now bird migrations were thought to have been far less important during the last ice age than today since seasonality was less pronounced during this time. Somveille and his team showed that birds are likely to have remained migratory throughout the last 50,000 years.

“The paper proves that bird migration is flexible and many birds are quite adaptable to change their migration pattern according to environmental conditions,” said Asad Rahmani, ornithologist and former director of the Bombay Natural History Society, who was not involved in the study.

However, Rahmani said, “in nature, things change rather slowly as compared to environmental changes, and extinction crises that we humans have brought to this world in the last 200 years.”

The researchers used a model to simulate the seasonal geographic distributions of birds across the world based on the interplay between access to resources, and the energy the avians had to spend in travel to obtain them. According to their simulations, bird migration has remained globally important despite major climatic changes between the last glacial maximum, or ice age — around 20,000 years ago — and the ongoing interglacial period.