In article ,
(diane) wrote:

Many years ago an elderly lady told me to fill mason jars half full
of water, put on lids and lay on their sides in garden. Seemed to have
detered rabbits back then. No rabbits around here now though, Coyotes
took care of them up here in northern Michigan


http://community.webtv.net/viditom/FlowersJuly172006

Got me thinking about this. I'd guess the water on its side acts like
a prism. Slight movement and the light flashes sightly . The effect
would sort of mimic the glint of a predatory hawks eye glint.
Soft of a home made deterrent that is based on fear.

http://www.allpestexpress.com/rabbits.aspx

From above URL "spinning aluminum pie pans and glass jars of water
have been used to frighten rabbits"

--
Bill S. Jersey USA zone 5 shade garden
What use one more wake up call?