On Sat, 10 Mar 2007 09:19:25 -0500, PeterD wrote:
Why worry about it... His yard, his pets, his life...

I *think* what the OP is worried about is that his friends' pets are being
scared off by his freinds' neighbor.

While I hate to discourage anyone from building something electronic, I do
have to ask: what will one do if they learn that a bird-scarer *is* in
use? Best of my knowledge, they aren't illegal.

If a bird-scarer works on dogs, then I find the details quite interesting.
May have to work up a mobile version. Loose dogs allowed to roam a
neighborhood are a serious safety issue for cyclists. (and I wonder if
that's why the neighbor in question is trying to scare them off?)