Scenario:

Living in the middle of a small estate and where at least half a dozen other
owners have decided to supply food to the local bird population all year
around by fixing bird feeders in their gardens.

That constant flock of birds to the feeders has now caused the rather
annoying problem of bird crap being dropped everywhere in my garden causing
quite a mess and nuisance (and possibly a health hazard to my
grandchildren).

The biggest problem though is with the constant coming and going of fairly
large numbers of jackdaws, magpies, starlings and blackbirds with the odd
crow showing up.

What I can't do:

Get rid of the feeders, the neighbours have politely told me that.
I don't wish to get banged up for using a shotgun!
I have a small calibre air-rifle that can 'tickle' the bigger birds to move
them (I don't wish to invest in a high velocity .22 as dead birds lying
around in various gardens etc.

Now the question:

Can anyone therefore suggest a good, effective, non-noise making bird scarer
that would go a very long way to scaring the little beggars off?

Many thanks