It’s thought that just seven hedgehogs were introduced to South Uist in 1974 – to control slugs and snails in a domestic garden. Since then the invasive carnivores have spread across South Uist and Benbecula in the Outer Hebrides. Today, 15 years after work started to prevent hedgehogs from reaching North Uist, it’s estimated that they number around 5,000.
Ringed plover on ploughed machair, South Uist
The Uists and Benbecula are home to internationally important wader birds, many of which nest in the islands’ machair – a globally rare habitat only found on the north-west coasts of Scotland and Ireland. Local wildlife is recognised as key to the Outer Hebrides’ growing £53 million per year tourism industry and the birds are a big attraction for many visitors to the islands.
As hedgehog numbers increased, ground nesting birds including lapwing, dunlin, ringed plover, snipe and redshank have seen their numbers decline. Research demonstrates this is mostly due to the non-native hedgehogs.
A dunlin nesting on South Uist Machair
A 1983 survey found at least 17,000 pairs of waders nesting on the Uists, including around 25% of the UK’s breeding dunlin and ringed plover. But a repeat survey in 1995 found waders had fallen significantly on South Uist and Benbecula, while numbers on hedgehog-free North Uist remained stable or increased. Another 1995 study confirmed hedgehogs were common throughout areas of machair on South Uist and Benbecula and that they were preying on waders’ eggs.
Experimental use of hedgehog-proof fencing in 1998 found that keeping hedgehogs away from nesting areas doubled hatching success for the waders. However, fencing could only provide a short term solution over a limited area. The Uist Wader Project (UWP) was established in 2000 after a further study revealed the full extent of the declines and confirmed dramatic north-south differences in the fortunes of these birds.
Redshank
Uist Wader Project partners included SNH, the Scottish Government, RSPB Scotland, Scottish SPCA and Uist Hedgehog Rescue (UHR) – a coalition comprising Advocates for Animals, British Hedgehog Preservation Society, Hessilhead Wildlife Rescue Trust and International Animal Rescue.
The 2000 study showed that in South Uist and Benbecula, numbers of breeding snipe, dunlin and ringed plover fell by 60%, redshank declined by 40% and lapwing by 30%. This contrasted with an increase in lapwing and redshank numbers on North Uist and although dunlin declined by 30% here, it was half the decline in the south.
Lapwing on Benbecula machair
The latest research shows this worrying pattern of decline to be continuing. Scientists believe the level of predation is so high that wader numbers will not recover unless the hedgehogs are removed. In response, we announced plans last month for a fresh programme of work that will aim for the long term recovery of the islands’ wader populations and support the local economy.
Snipe are often seen standing on fence posts
Animal welfare is at the heart of this work, which will continue to see hedgehogs safely trapped and humanely moved to their native range on the mainland over a 10 year period. The plans have been backed by a range of organisations and community leaders and we are now developing a detailed project proposal and an EU LIFE funding bid. If this is successful, work to remove the hedgehogs is expected to start in 2017.
For more information visit the Uist Wader Research pages on our website.
Scotland's Nature 
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