Let me tell you about the bats and the birds and the beetles and the turds…

From ANIMAL PEOPLE, October 1999:

LONDON––Trying to bring a rare
bird called the clough back to Cornwall, the
National Trust on advice of English Nature in
1996 banned the use of avermectin-class vermicides,
including Ivermectin, in cattle who
graze NT pastures. Residues from the wormkillers
were believed to be inhibiting the reproduction
of dung beetles, the clough’s chief
food source. About 100 farms were affected.
There are still no cloughs in Cornwall
––but the rare greater horseshoe bat has become
more numerous within the 100-farm area than
anywhere else in England, and the even scarcer
hornet robber fly has appeared as well.
Even with the Cornwall bat boom,
there are still fewer than 4,000 greater horseshoe
bats in Britain, among just a handful of
colonies. English Nature and The Bat
Conservation Trust hope to persuade other
farmers to forgo the use of avermectins.
“And I thought the new highly efficient
parasiticides only eradicated parasitologists,”
said World Health Organization epidemiologist
Martin Hugh-Jones.