These days, birdstrikes are less of a danger to life - except to low- flying military pilots - more an expensive nuisance. Modern jet engines can usually digest an unfortunate seagull without much more than a hiccup and only big birds like geese are likely to smash through cockpit windows.
But even the largest airliner has a remarkably thin aluminium skin. The dents produced by birdstrikes can be very expensive to repair because of earnings lost while the dented aircraft are fixed. And while the risk to airline passengers is low, it still exists. No-one can afford to ignore it.
The Civil Aviation Authority is particularly concerned about landfill sites within 12km of airports. On 'dry' sites like Ugley the biggest threat comes from seagulls, which will travel up to 50km to feed, crossing flight paths on the way. Flocks of starlings can also be a hazard, but they rarely stray far from their own territory. Where there is open water on the site the much larger Canada geese are a major problem.
Apart from total enclosure, the CAA favours such measures as the broadcasting of distress calls, the destruction of local nests and eggs and the culling of adults. Enclosures like Ugley are obviously much less controversial.
Hales site manager Richard Hill says the enclosure has proved to be a complete success at keeping the seagulls off the waste.
'They still send scouts across from time to time, but they won't go under the net to feed.
'We have been able to dispense with the plastic strips at the entrance as well. And besides having no problem with litter from the site, local residents don't have hordes of seagulls dropping scraps of rotting food into their gardens either.'