How to stop birds sh*tting on our swing

[Legend83]

We have a lovely wooden-framed swing for the children in the garden but it would appear birds are enjoying having a perch on the wooden cross-beam and emptying their bowels all over the swing seat.

Any bright ideas on how to put them off? I considered wrapping and affixing some holly round the beam as that can't be too comfortable to sit on!

[Legend83]

Thanks for the very useful and practical suggestions chaps!