Upper Clear Creek, a Port of Tacoma habitat site, is a wetland filled with birds.
But you can’t always see them.
Scott Markowitz of Puget Sound Bird Observatory calls them “secretive birds.”
“You may be lucky enough to see a Virginia Rail,” Markowitz said. “But what you're not getting are the six other Virginia Rails in the immediate area.”
That matters when counting birds, which Markowitz did this spring in the 40-acre site.
The Port’s site is part of the region-wide Wetland Secretive Bird Monitoring project launched by the Puget Sound Bird Observatory in 2016.
Along with Port of Tacoma biologist Kristin Evered, Markowitz visited to play audio recordings of bird calls, and then count how many answered.
“You’re really tested as a biologist and as an observer to sort of figure out where the noise is coming from,” Markowitz said. “Is that an individual here, an individual there?”
The process follows a stringent protocol to ensure accuracy.
Markowitz and Evered started with five minutes of silence, then played a call and listened for one minute, counting how many of that species called back.
They played the call from another species, then listened and counted for another minute.
In all, they played the calls of five species; Virginia Rail, Sora, American Bittern, Green Heron, and Pied-billed Grebe.
Marsh Wren and Willow Flycatchers are also monitored, but their calls aren’t played because they are vocal species.
The Upper Clear Creek habitat site was constructed in 2016 and is in year eight of ten years of required performance monitoring.
“The data that we gather from these surveys is not only important to the Puget Sound Bird Observatory, but also is important for us knowing what birds are accessing our habitat site,” Evered said.
Markowitz first noticed the mitigation site when he drove by soon after it was planted.
“It was just dirt with a few snags stuck in and you don't put snags in a gravel pit, so I knew there was something going on,” he said.
The site is not open to the public, so Markowitz contacted the Port of Tacoma for access and has been conducting the annual bird survey for several years.
He’s seen Upper Clear Creek fill in with vegetation and become a wetland that now attracts beavers, otters, fish, and birds.
“There’s amazing stuff out here,” Markowitz said. “The site is just really good for wildlife.”
Visit the Puget Sound Bird Observatory website to learn more about the Wetland Secretive Bird Monitoring project or to find out about volunteer opportunities.