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Rats Gone, Seabirds Bloom on Scottish Isles
4 Oct
Summary
- Rat eradication on Canna and Sanday islands completed in 2006.
- Atlantic puffin populations increased significantly post-eradication.
- Rabbit population exploded following rat removal, causing damage.
In February 2006, the complete eradication of rats from Scotland's Canna and Sanday islands concluded. This project, initiated in December 2005, aimed to restore the islands' ecosystems. A decade of monitoring revealed that seabird populations responded uniquely to the absence of rats.
Atlantic puffins, previously confined to limited areas, expanded their range significantly across Canna. Their numbers rose from 1,190 individuals in 1995 to 2,050 by 2016, indicating increased breeding success. Manx shearwaters, however, demonstrated a slower recovery. While nesting resumed after rat removal, populations remained very low, with only a few nests recorded by 2017.
European shags showed clearer positive changes, with one colony growing from 45 to 75 nests between 2005 and 2016, and average productivity improving significantly post-eradication. Other seabirds like mew gulls also increased, though guillemots continued to face challenges from storms and food shortages. The removal of rats also coincided with a dramatic increase in the rabbit population, estimated at 15,500 by 2013, leading to significant damage. Intensive culling programs were implemented to control the rabbit numbers and mitigate further environmental impact.
