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Future up in air for bat colony

Woodard Bay: Restoration plan might jeopardize roost of thousands

JOHN DODGE; The Olympian | • Published June 22, 2009

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As dusk turned to darkness, 2,251 mouse-sized brown bats and Yuma bats flitted from beneath the 3,000-foot-long pier that spans Chapman Bay at the Woodard Bay Natural Resource Conservation Area, bound for a night of feeding on aerial insects at Capitol Lake in Olympia and other distant locales.

The bats – all females – would return that night to feed thousands of even smaller, hairless babies, many of them born within the last week at what is the largest known maternal bat colony in the state.

Armed with hand-held counters, volunteer biologists Mary Linders and Lori Salzer tallied the bats, a weekly summer ritual of theirs that began six years ago.

“We had 4,500 bats last week,” said Linders, sharing her field data Thursday night with a few onlookers drawn to the site, despite the fact that the sprawling, 800-acre property owned by the state Department of Natural Resources is off-limits after dusk to all but wildlife researchers such as Linders and Salzer.

“Maybe some of the mothers are staying on the roost tonight with their young.”

The bat tally June 11 shattered the previous single-night record of 3,500, a number that included baby bats taking flight.

There’s still much to learn about these nocturnal creatures that weigh no more than a nickel. Researchers don’t know where they scatter to when they leave the roost in late summer, Salzer said.

About the only thing certain about the bats is that their future at Woodard Bay is uncertain.

DNR has started work on plans to remove some of the man-made structures that clutter the shoreline and nearshore areas at the conservation preserve to improve water quality and tidal flows and create a more natural habitat.

The 5 miles of shoreline and Chapman and Woodard bays on Henderson Inlet are filled with an old pier, a trestle, log booms and hundreds of pilings left from when the site several miles northeast of Olympia was a Weyerhaeuser Co. log-sorting and -rafting operation.

But in the 25 years since Weyerhaeuser abandoned the site, and 11 years since DNR bought it to conserve it, some of those man-made structures have become havens for wildlife.

For instance, a small section of the pier across Chapman Bay is seasonal home to the bats. And some of the log booms beyond the pier are home to the largest harbor seal nursery in South Sound.

In sharp contrast, a variety of species, including juvenile salmon and native Olympia oysters, could benefit from the restoration work, noted Betsy Lyons, a Seattle-based marine conservation project manager for The Nature Conservancy.

The importance of the abandoned pier to the bats is not lost on DNR, said Michele Zukerberg, Woodard Bay project manager for the state agency. That’s why all four restoration alternatives leave the pier roosting area in place, she said.

But three of the four options remove anywhere from 38 percent to 76 percent of the pier.

That could spell trouble for the Woodard Bay bats, said Olympia bat researcher Greg Falxa, who was the first to document several years ago that the bats flew as far away as Capitol Lake to feed at night.

For instance, he said, the bats fly under the pier when they depart and return each night, perhaps to protect them from predators, including owls.

“Without the pier, the roosting area might not be as attractive to them,” he said.

Falxa is urging DNR to work on alternative nesting structures at Woodard Bay before they start dismantling any of the pier.

“Relocating wouldn’t be as successful as leaving in place the pier habitat that they use,” Zukerberg suggested. She described the pier as a sturdy structure that the bats could use for decades before it fell apart.

Falxa disagrees, saying some of the beams in the area where the bats roost are falling into the water.

Meanwhile, all but the status quo alternative call on DNR to maintain or improve – but not increase – the seal haul-out area.

All of the options would lead to removal of hundreds of creosote-soaked pilings and the old Woodard Bay trestle.

However, there is no great urgency to remove the pilings from a pollution standpoint because tests show very little sign of chemicals from the creosote wood preservative in the sediments, Zukerberg said.

That’s probably a good thing, because DNR doesn’t have any money in its budget to do any of the restoration work, which is estimated to cost $2 million to $5 million.

“We’ll probably have to rely on grant funding and do the work piece by piece,” the project manager said.

DNR is working with Windward Environmental of Seattle on a $150,000 feasibility study that should identify a preferred alternative by September 2009.

John Dodge: 360-754-5444

jdodge@theolympian.com