Spring 2001 Table of Contents

Heron rookery rescued!

A Great blue heron rookery, or communal nesting site, would be a bonanza for any backyard wildlife sanctuary since these four-foot-tall, prehistoric-looking birds don't nest just anywhere.

They set up spring housekeeping together in large groups in the same place year after year, which is why it's so important to preserve the habitat that commands their loyalty; big, tall trees that can support their huge, annually-re-used nests, along a waterway where they can fish.

So when WDFW's urban biologist Michelle Tirhi got a call last November about heron nests destroyed when a stand of alders in a riparian area near Tacoma were felled, she jumped into action to make sure the birds would have something to return to this spring.

The concerned caller, Harlan McChord, agreed to have salvaged heron nests re-located in trees on his property, adjacent to the scene of destruction.

About 20 people, from five government agencies and non-profit groups, plus one family with their home-schooled children, assisted Michelle in extracting 30 nests from the trees that had been cut down. Some nests were picked up intact off the ground, she reports, while others had to be cut out from under debris. The group constructed plastic mesh baskets, to hold the nests and to haul them up the new trees.

Two tree experts, Tim Brown and Randy McDougal, donated several days of climbing and positioning the nests in the trees, and trimming branches around the relocated nests to open up the canopy so herons could use them again. In February, Michelle, Harlan, and Tim hauled four life-sized heron decoys into the trees surrounding the relocated nests. In March, two more decoys were placed directly on nests.

Michelle has been playing a tape-recording of a heron distress call in breeding season at the site every other day to attract herons.

"Within the first ten minutes of playing that tape,"Michelle recalls, "I had 17 herons fly into and attempt to perch on the trees holding the decoys!"

By early March, about 50 herons were moving between the old site and new location. At that time, none had laid eggs at the new site, however.

"Great blue herons are so loyal to these communal nesting sites," Michelle says, "that I'm not sure how successful we'll be in this effort. There's an active red-tailed hawk nest close by, and I'm not sure what impact that will have. But I think there's a 50-50 chance that these herons will adapt to this change."

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