Just a note:
The U Vic group states, "Living in such close proximity with humans means
that habitat loss is the biggest threat facing the great blue heron. Not
only do they require good, relatively undisturbed foraging territory, but
the herons are picky nesters, and have been known to abandon their eggs if
the nesting site is disturbed or becomes too noisy. They require high trees
in which to nest, and these trees must be within three kilometres of the
prime foraging ground. Once one of those conditions is affected by human
activity, the others become useless, compounding the effect of habitat loss
and leaving seemingly perfect land unutilized by the birds."
Thanks for the info Carl.