Bird Migrations Set To Increase: Added Distance Is 'Considerable Threat' To Some Species

A team of researchers - led by Durham University and with funding from the RSPB (BirdLife in the UK) and Natural Environment Research Council – looked at the migration patterns of European Sylvia warblers, a group of birds that are common residents and visitors to Europe, like Common Whitethroat Sylvia communis and Blackcap Sylvia atricapilla.

“Our findings show that marathon migrations for some birds are set to become even longer journeys”, said Dr Stephen Willis – team leader from Durham University. “This is bad news for birds like the Common Whitethroat”.

Some 500 million birds are estimated to migrate to Europe and Asia from Africa. Birds weighing as little as nine grams undertake the annual migration of thousands of miles between the two continents to find food and suitable climate.

“Most warblers come here in spring and summer time to take advantage of the surplus of insects, and leave for warmer climes in the autumn”, added Dr Willis. “From 2071 to 2100, nine out of the 17 species we looked at are projected to face longer migrations, particularly birds that cross the Sahara desert”.

Co-author of the research paper, Professor Rhys Green of Cambridge University and RSPB said: "These tiny birds make amazing journeys, pushing themselves to the limits of endurance. Anything that makes those journeys longer or more dependent on rare and vulnerable pit-stop habitats used for refuelling on migration could mean the difference between life and death.”

"We have already seen evidence that birds' ranges are moving north to track suitable climate conditions in the way predicted by past modelling”, noted Professor Green. “This latest research suggests they will face an increase in the length of an already arduous journey.”

In response to worrying declines of many migratory species, BirdLife has launched the Born to Travel Campaign to protect migratory birds along the African-Eurasian flyway. “These birds face many threats during their incredible annual journeys”, said Richard Grimmett – BirdLife’s Head of Conservation.

“BirdLife and its Partners are working to provide a safer journey for migratory birds”, added Mr Grimmett. “We have BirdLife Partners in over 70 countries across the migration routes between Europe, the Middle East and Africa, and are working together to tackle threats to migratory songbirds like agricultural intensification, desertification, deforestation and climate change”.