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Climate change hits migrant birds
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This weeks feature
The numbers of migrant birds reaching our shores during the spring is being deeply affected by climate change, according to figures supplied by the public and assessed by environmental groups.
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Not enough food... |
Thousands of birdwatchers across Britain and Ireland, who contributed to the online bird-recording project BirdTrack, recorded fewer swallows, chiffchaffs, willow warblers and spotted flycatchers arriving back in the UK in 2005.
Using the lists of birds recorded on the internet, BirdTrack - a joint venture by the British Trust for Ornithology, RSPB and BirdWatch Ireland - estimated that the number of swallows was 15 per cent down on 2003 and 2004.
Poor weather on migration, particularly in North Africa and southern Europe, meant that birds did not find enough food to re-fuel properly after their long journey across the Sahara. For those that reached Britain and Ireland, the cold weather in April brought further problems. |
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Other species, most notably the chiffchaff - a small warbler that winters in North Africa and Iberia - were 20 per cent down on 2003 and 2004, while willow warbler, whitethroat and spotted flycatcher numbers were also down.
All these species rely on insects to survive, and the cold and wet weather during the spring made it more difficult for them to find food. |
Some of Britain’s resident species, like the blue tit and great tit, have also had a mixed breeding season, with dead chicks found in many nest boxes.
The reasons for the deaths are unclear, but a combination of poor weather leading to chilling of chicks and the inability of adult birds to find enough caterpillars to feed the young will have contributed.
“Migration and breeding are very stressful times for birds and poor and unpredictable weather during these times can mean the difference between life or death for birds,” says BirdTrack organiser Dawn Balmer. |
An unproductive summer? |
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“For some species it might mean that they abandon breeding this summer if there is not enough food available for them to keep in good condition. Many of our migrant visitors will only have one breeding attempt each year, so it could prove to be an unproductive summer.”
Birdwatchers can help track the fortunes of our birds by submitting their bridwatching lists to BirdTrack at the website www.birdtrack.org on a regular basis. |
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