[Mike]

http://www.duluthsuperior.com/mld/duluthsuperior/news/local/8611195.ht
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ASSOCIATED PRESS

HAYWARD, Wis. – A hail storm killed more than 100 great blue herons
on a Chippewa Flowage island, but the loss shouldn’t affect the
statewide population of the graceful wading birds, state game
managers say.

Still, it demonstrates how susceptible wild birds that live in large
colonies can be to the severe weather, according to workers with the
Department of Natural Resources.

The storm hit April 18 and the deaths were discovered on Little
Banana Island on April 30 by the DNR wildlife staff following up on a
citizen report.

In the rookery, or colony of nests, workers found 106 dead herons and
another 11 injured birds. About 50 herons at the site were unharmed.

The DNR crew managed to capture the 11 injured herons and deliver
them to a local wildlife rehabilitator.

Laine Stowell, one of the DNR biologists who visited the site,
estimated that at least 100 heron eggs were smashed on the ground.

The storm that hit the area included hail and high winds that damaged
homes, cottages and vehicles and stripped needles from pine trees.

The DNR staff made an aerial survey of the flowage April 20 to check
on the rookery but observed little damage, with most of the nests
still intact. However, the citizen report about injured herons along
the island’s shore caused the DNR staff to investigate and find the
dead and injured birds.

“The structural damage to the rookery was less than expected
considering the loss of all those birds,” Stowell said.

He said biologists believe about two-thirds of the rookery population
was killed.

Bill Volkert, a DNR wildlife educator at Horicon Marsh State Wildlife
Area, has worked extensively with colonial nesting birds.

He said the incident underscores the natural risks faced by many such
birds.

“With colonial nesting birds, there is always the risk of losing a
whole breeding population in one major natural event, such as a major
thunderstorm with high winds,” Volkert said. “While building nests in
trees protects them from predators, it makes the rookeries vulnerable
to severe weather.”

He said it could take two or three years for the rookery to rebound.
Some of the remaining herons will probably try to resume nesting, but
they probably will produce fewer offspring.

While the event will affect the local heron population, it won’t have
a significant statewide impact, Volkert said, noting that a recent
survey showed great blue herons nest in all of Wisconsin’s 72
counties.