Monitoring results within the Ark
Predator control started early in 2003. The reduction in rat numbers has been spectacular - since 2007 the usual result of monitoring is to find just one visited tunnel out of the 100 placed throughout the Ark.
The initial increase in mouse numbers was attributed to them flourishing in the absence of rats, but since 2006 their numbers have also dropped sharply - this was unexpected, but has been sustained and it now seems clear that the combination of broudifacoum and a 100m by 50m grid of bait stations is sufficient to significantly reduce mouse numbers. Click the forward arrow above to compare with the results of monitoring outside the Ark.
(Click on magnifying glass icon above to see an enlarged view)