[Ralath]

This story is kind of hilarious.
http://online.wsj.com/article/SB1000...249634496.html

In 2000, trees were sprayed with a concoction made from ground chili powder, hot chili sauce and glucose, but the authorities returned the next morning to find more bats there than before.

The next step involved a trip to an Asian supermarket to buy fermented shrimp paste—which the Bat Club noted is used in Southeast Asia as a flying-fox repellant on commercial fruit trees. Six bats sprayed with the paste were seen "intensely grooming and wing licking," but didn't fly off, according to a Royal Botanic Garden report.

Python excrement laid in 2001 to trick the bats that predators were crawling around was more effective. Bats roosted a few meters away, but a wider rollout of the trial was shelved due to the difficulty of sourcing supplies.

Other efforts that disappointed included plastic bags of toilet-deodorizer blocks, strobe lighting, a theatrical smoke machine, tape recordings of bat distress calls and use of a home-garden sprinkler containing a water and honey solution.

Several ideas failed to make it off the drawing board, including covering all 3,800 trees in the garden with giant nets.