Re: Cat warning device for backyard birds.

Eric,

Bells on cats DO work.  They need to weigh one kilogram!

Seriously, I have reservations about the usefulness of the electronic
beeper device.  Such a noise has no significance for a bird, and is
unlikely to scare it off.  If it beeps  constantly, then birds will
habituate to it rapidly (until the cat gets them).  By all means try it,
but I believe the only effective way to stop a cat preying on birds (and
lizards, frogs, mammals, insects) is to keep it confined, either in the
house or in an outdoors cat pen.  Several designs are on sale in Victoria,
where there is legislation aimed at encouraging responsible pet ownership.
This includes confining cats to some extent.

Cheers

Ian