It doesn't have to be fancy bird silhoutte shapes stuck on - which could be peeled and 'piggled' off by local kids with nowt better to do - painting a black cross diagonally across each glass would work. All that is needed is black (or green if the shelters are green) paint, masking tape and a small paint brush.... request that the council does it - if you do it yourself it will be seen as vandalism and removed by the council - so get in touch - try your local councillor - get the local paper involved - get your pic in the paper asking for this job to be done - take photos of the dead birds - get local paper to photograph make a story out of it and I think you might find it will be done quite quickly
Pauline