Do Midge Magnets Work?

The midges have been out in force this last week or so and our midge magnet has certainly been earning it's keep. The bottom of this reservoir would hold the best part of a litre of water if it weren't quite so full of midges. Last year there were less than this throughout the whole season.
In case you're wondering, the reservoir gets rinsed in the stream so the fish get a tasty snack :-)