Graybeard,
Thanks, I didn't realise average power of the more modern solid state radars was that low.
Canuckbirdstrike,
You clearly have studied the subject, I haven't, so I take your word for it.
I just thought of another point "for the prosecution"....
Most airports have one or more operating radars, some even inside the airport perimeter, most with lots more power than a weather radar.
Hasn't kept birds off airports, now, has it?
So even in the hypothetical case that birds can sense a nearby radar, adding your weather radar to the "noise" (to them) is unlikely to impress them.
Sorry, Loo, but the consensus seems to be that turnng the wx radar on to scare the birds is about as much use as hanging a St. Christopher medal on the standby compass.
CJ