"Eric" wrote:

As far as the herons are concerned I have found that two pairs of CDs
suspended just above the water appear to have completely frightened the
herons away. They look just like a pair of eyes and rotating in the
slightest breeze creates an ever changing pattern of flashing spectral
colours. (At last I have found a use for all those blasted AOL CDs they
send me!)
----
A friend who has a large pond was troubled with a heron that often dropped
in for an early breakfast. She tried putting a low wire around the
perimeter, that didn't work. When on the point of conceding defeat to the
bird, she found a life-sized, suitably painted resin grey heron. She
positioned it looking into the water from the bank and has had no further
visits from real herons. As resin heron was so lifelike, she did wonder if a
real heron might just take a fancy to him/her. Perhaps one did and found the
experience hard going!

Rusty