Brown Rat

Dark blue dots show records since 2000
Mid blue dots show records from 1990 - 2000
Light blue dots show records from before 1990
.
Rats are probably the least popular mammal in the country, and few people bother to record them.
.
Brown rats were eradicated from Ramsey Island in 2000, and have not been recorded there since. This has enabled some ground/burrow nesting birds to survive better there. Rats are not found on Skomer or Skokholm - one that was seen swimming ashore on Skomer in the 1950s was caught within 24 hours, and none have been seen since.