In message , Les Crossan
writes
I did think to construct something akin to the 'spikes' used in
cities to deter pigeons perching, but wondered if anyone could
suggest a quicker fix.

A cat??? House sparrows have become quite rare so perhaps a non -
lethal deterrent might be a better idea. What about a stick - on hawk
on the house window??

Cat - not on. Too many birds around the feeders (which are located well
away from the gauge). I even have a 'tame' female sparrowhawk who drops
by twice a day (pretty regularly too, 9am and 3.30pm), but they are all
back within 30 seconds of her moving on.

--
Chris