Cavity creation bridges gap for many species

Bob Reinert/Northwest Guardian

Members of rare, uncommon or declining species looking for homes could do worse than Fort Lewis.

Here, they receive help from Jim Lynch and Sanders Freed, a pair of biologists dedicated to putting roofs over the heads of wildlife with a “cavity-creation” project designed to encourage biodiversity on post.

“The cavity-creation program focuses on providing nesting cavities for these species in either living or recently killed trees,” said Lynch of Fort Lewis Fish and Wildlife.

“None of the species we’re providing cavities for are federally endangered species,” Lynch said. “The major focus of our program in general is to stabilize or increase populations enough that listing (as endangered species) is no longer needed.”

In that effort, Lynch partners with Freed of The Nature Conservancy. In recent years, they have carved cavities in trees around the installation to accommodate such species as the western bluebird, purple Martin, wood duck, American kestrel, hooded merganser and western gray squirrel.

“You’re looking for large-diameter trees when you’re doing this work, because they’re the only ones that will facilitate a large enough cavity,” Freed said. “You do need to pick your trees.”

Lynch added that he and Freed don’t want to select trees that might interest loggers. He pointed to a number of straight, tall trees that would make perfect telephone poles before his eye settled on an aged, crooked candidate.

“When that thing rots, it’s going to have so much character to it and so many different opportunities for wildlife,” Lynch said. “That’s the kind of tree that we take.”

Then Lynch and Freed use a chain saw to carve out a cavity. The bark that’s removed becomes a faceplate with openings for animals to crawl through. Just what inhabits the space can be surprising.

“The different species that also used the boxes was what was really interesting to me, because we had everything from bumblebee hives to bats in these cavities,” Freed said. “Just the array of species that are looking to call (these) home out here is astounding.”

Freed said that their monitoring has revealed high levels of usage in the larger cavities they created.

“Our first-year cavities seemed to get about 50 percent use,” Freed said. “Cavities that have been in existence two years in a row, they had over 90 percent rates of use.

“So when you put a cavity in a tree, things are going to use it, is the bottom line, because there’s an apparent lack of these.” Lynch said the idea is to create habitats that will stand the test of time.

“What if I’m not here tomorrow?” Lynch said. “By using cavities ... we help bridge the gap between a present that lacks old-growth forest characteristics like large snags with dozens of cavities within them and a future that, on Fort Lewis, very likely will.”

Lynch said Fort Lewis is fortunate to have The Nature Conservancy as a partner in working toward biodiversity on post. “There’s a very strong scientific background at The Nature Conservancy,” Lynch added. “When they come to the table and talk to us, you’re talking eye to eye.

“You’re able to share knowledge and experience. They bring a lot to the table.”

According to Freed, The Nature Conservancy is glad to help.

“We’re really excited to be involved in the efforts of basically maintaining and stabilizing every, single species that they can in this really unique landscape here in the middle of the South Sound,” Freed said. “For this region, it’s a gem.”