For those who haven't heard:
Great blue herons abandoned a heronry on McAllister Creek near Nisqually
Wildlife Refuge. Bald eagles were seen feasting on chicks.

Before you blame bald eagles only, consider some research:

Herons will move a heronry, if disturbed by humans, several studies show.
When people bother great blue herons during nesting time, the heronry
reproductive rate often takes a nosedive or the herons move. Herons also
need undisturbed areas for winter foraging. (Source: Robert Butler, "The
Great Blue Heron.")

The heronry along McAllister Creek had a lot of human disturbance from all
sides including: nearby clear-cuts, construction, housing, lawn mowers,
target shooters in nearby woods, Nisqually refuge trail crowds, power
boaters, anglers, kayakers, canoeists, beachcombers, dog walkers, and
sightseers. (The Nisqually/McAllister heronry was rated "high" for human
disturbance by one study. Source: "How Many Herons Do We Want?," Puget Sound
Research Proceedings '95.)

It doesn't take much human activity to spook herons away from nesting sites
for good; One waterfront landowner on Whidbey Island started construction of
a road to his house near a heronry during nesting season. The bulldozer
scared away the entire colony of herons and they never came back. (Source,
ibid., p. 731)

The decline in great blue herons is a most likely due to a heckuva lot of
humans and a few bald eagles.

Robert Butler said it best in "The Great Blue Heron":
"The future for the heron does not look very rosy given the projected growth
in human population around the Strait of Georgia and Puget Sound

Compounding the problem of human disturbance is the increase in disturbance
from bald eagles."

Tammy Pelletier
Olympia, WA
e-mail: greg at halcyon.com