Bird deterrent recommendations

[Mamabear04]

I'm looking for ideas of how to deter birds from my garden. I have a big tree and they like to perch there but they shit all over my kids trampoline/shed/grass. I don't mind the birds but I would like less of them. I've thought about buying a bird of prey model to scare them and also saw shiny reflective hanging things on amazon to deter them. Any recommendations or advice?

My next door neighbour strings CDs among her fruit to deter birds. It must work because she gave me loads of fruit this year.

Bloody pigeons. They land on my glass roof and then slide down into the guttering to get water. The gutterings are not designed to hold a kilo of pigeon and are slowly getting destroyed.

I am thinking of creating a drinking bath for them, but knowing animals they will probably prefer to carry on drinking the sludge infested fetid water from the gutterings rather than drink from a bird bath.