A:

The total number of unnecessary bird deaths caused by crashing into windows must number millions.

Birds are at their most vulnerable when they can see light on the other side of glass, as is usually the case with conservatories.

The best way to stop further deaths is to put up warning stickers. Most commercials stickers, which are available from garden centres or RSPB shops, are designed to resemble flying hawks, but any sticker is likely to have a similar effect.