http://news.bbc.co.uk/2/hi/science/nature/4056691.stm
including
>The rabbit population is now estimated to be 40 million.
>It has risen by around 10% in 10 years. [Put here due to food source]
>...But the most spectacular rise documented in this survey is that of
>the polecat...
>Its population has grown from 15,000 to more than 60,000 in a
>decade - partly, according to Mammal Society Chairman Michael
>Woods, because gamekeepers are no longer suppressing its numbers...
>"The number of gamekeepers has declined dramatically, and the
>polecat has responded by expanding its range
[Badgers also up.  Otters up and introduced American Mink which
mainly got out in the 1950s down.]
>The return of the otter is bad news for the mink, whose numbers have
>slid from 110,000 to 37,000...out-competed and sometimes out-fought
>by otters.
 
and
 
http://news.bbc.co.uk/2/hi/uk_news/england/oxfordshire/3220457.stm
including:
>Zoologists at the University of Oxford have now found the reintroduction
>of otters along river banks has caused mink numbers to drop...
>Almost immediately mink numbers fell by 75% and since then have only
>recovered slightly... Similar results were found in south west England.
[Posted in FML issue 4718]