Introduction
The islands of Canna and Sanday are situated off the West Coast of Scotland within the Inner Hebrides, close to the island of Skye. The islands are closely situated and are connected by a pedestrian footbridge. Both the islands are served by Caledonian MacBrayne ferry from Mallaig.

Over the past thirty years Aberdeen University has been collecting data on breeding seabirds through the 'Seabird Monitoring Programme Canna Studies'. The Highlands Ringing Group who carry out the seabird-ringing programme has been instrumental in the collection of this data. The data collected has clearly identified that some species of seabirds are in decline. The evidence collected strongly suggests that the main problem is predation on eggs and small chicks by rats.

Manx Shearwater is one species that is suffering mainly from rat predation. Manx Shearwater nest in burrows within a colony and are easy prey to rats. The Trust has tackled the problem by introducing rat bait boxes within the colony at the time of year when rats are looking for food after a long winter so they visit the Manx colony. This has helped to keep the rat numbers down but unfortunately the Manx Shearwater is now extinct as a breeding bird on Canna.

Rat Eradication Programme
The Trust has initiated research in 1998 aimed at looking at the effects of rats on other species. As part of this research a student from Edinburgh University, under guidance from Trust staff and as part of their Masters degree, carried out a small mammal survey in 1999 on the island of Sanday. This showed that the numbers of small mammals are low. This may be in part a result of rat predation and more in depth research is required.

Research into secondary poisoning in the food chain has been carried out in relation to birds of prey. The research has shown that rabbits who have ingested warfarin and have then been eaten by a bird of prey do not pose any threat to this species.

The next stage
A rat density study has shown us where the rats are located over the winter period. This is the ideal time for eradication as they are at their weakest. We expect to begin this programme in 2005/6 and a result of these efforts it is envisaged that the island's wildlife will thrive for future generations to enjoy.

For further information on this project please contact:

Abbie Patterson
National Species Recovery Officer
The National Trust for Scotland
28 Charlotte Square
Edinburgh
EH2 4ET

Telephone - 0131 243 9353
Email: apatterson@nts.org.uk