Birds are shifting their range 50 per cent slower than expected.

A study has found that European breeding birds are responding to recent climate change, but slower than expected.

The research, led by Durham University, found that, over the last 30 years, the birds have shifted their range by an average of 2.4km per year.

However, based on observed climate change, researchers have predicted that the average shift per species should have been approximately 50 per cent faster.

The study used survey data from two Europe-wide bird distribution atlases which were published 30 years apart.

The data revealed that colonisation and extinction events across species ranges were more influenced by climate at the time of the first surveys, with species only weakly influenced by climate change between the two survey periods.

This is due to the birds shifting their range to reach other populations of the species.

One of the main contributors to why a new area might be colonised or a population might go extinct is the extent to which the area had other populations of a species nearby.

This would facilitate colonisations and minimise extinctions, possibly due to the dispersal of birds from neighbouring areas.

The research suggests that maintaining networks of local populations will limit extinction events and make the populations more robust to climate change.

Joint study-lead Professor Stephen Willis of Durham University’s Department of Biosciences said: “Our findings potentially show two intriguing responses to recent climate change. In some areas ‘colonisation lags’ may result in species being unable to track improving climate, perhaps due to habitat or prey not yet being available in new sites.

“By contrast, fewer extinctions occurring in areas where we predict them to occur might be evidence of ‘extinction debts.’

“Such debts occur when species are committed to eventual extinction due to unfavourable climate, but they nonetheless manage to persist, sometimes for lengthy periods, because key limiting factors, such as their preferred habitat, take some time to alter.”

The study has been published in the Nature Communications journal.