The proceedings of the September 2007 post project conference: Tackling the Problem of invasive alien mammals on seabird colonies - Strategic approaches and practical experience, jointly hosted by The National Trust for Scotland, Royal Zoological Society of Edinburgh and Central Science Laboratory at the Education Centre, Edinburgh Zoo are now available on line. Click on:

http://www.ntsseabirds.org.uk/File/Conference%20proceedings.pdf

Geoff continues to check the monitoring grid. Since the last report there has been three further complete checks. The table below shows the results. No rat signs were detected, but as would be expected the percentage of blocks nibbled by mice increased as the winter progressed. By November 91% of stations had mice nibbles, indicating that probably most of the island has now been recolonised by wood mice following the eradication.

Result of monitoring work; Rounds 8-10.

A team of three from RZSS also visited Canna for a week in November to assess the fieldmouse population. In 200 trap nights across a range of sites on the eastern half of Canna they captured 60 mostly adult apodemus all looking very large and very healthy. They also used 75 hair tubes at a number of sites, which again demonstrated a significant mouse population. Anecdotally, general accounts of mice and shrews suggest a substantial increase in populations of both particularly on Canna and to some degree on Sanday. The results mirror the data generated by WMIL using chew stick analysis at the beginning of the year.

Abby Paterson (NTS) has been visiting Canna to monitor the rabbit population. Here he reports on his progress:

"Now that rats have been removed from Canna other monitoring is necessary to measure the impacts of removing a major predator from the island. Rabbits were probably the main food supply for rats, particularly over the wintertime when other food sources were not available e.g., bird’s eggs and chicks, and monitoring began on rabbits in February 2007.

It was expected that rabbit numbers would go up and with that there would be an impact on the grass swards needed for the stock on the island. However, this did not happen this year and out of the four sites monitored, three showed a decline while one site had a slight increase. It has to be taken into account that this is the first year and we now have a baseline measure to obtain a more accurate account of rabbit population growth and decline on Canna for the coming years."

Monitoring work will continue over the winter. A WMIL team will return in March 2008 for the final check and will then remove all remaining bait stations.

Bob Swann, Project Administrator

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