If things continue as planned, the Mazama pocket gopher may well make a comeback on the mounded prairie at Wolf Haven’s facility between Tumwater and Tenino. The Washington Department of Fish and Wildlife and The Nature Conservancy have teamed up to try to make it so. Their actions are for good reasons. The species was officially added to the Washington State Threatened list in March, 2006. The press of civilization in western Washington is forcing this small mammal out of its home. Because it inhabits open, non-forested areas with well-drained soil, its habitat lies on prime development land. Add to this the intolerance of many landowners for the gopher’s burrow systems and earthen mounds, and you have a recipe for extinction.
The Mazama pocket gopher lives in the light but likes it dark. They
shun light, living underground. They keep all entrances to their
burrow system plugged. Open a gopher’s burrow and it will plug it up
again, usually within hours. Despite their love for dark places, they
require western Washington’s most sunlit grasslands to survive.
Gophers, in western Washington, inhabit prairies, pastures, road
margins and other open grasslands that benefit from exposure to full,
unfiltered sunlight. They are vegetarians, dependent upon the grasses
and forbs that grow in great abundance on prairies.
Residents of eastern Washington might easily fail to understand the concern for the pocket gophers of western Washington. Northern pocket gophers, Thomomys talpoides, are exceedingly common in many parts of eastern Washington. The western Washington species, Thomomys mazama, occurs in relatively few areas and at least two formerly recognized subspecies, Thomomys mazama louiei and Thomomys mazama tacomensis, are believed extinct. The main difference between the gopher of eastern Washington and the gopher of western Washington is quite simple. The western Washington species, Thomomys mazama, has a bigger penis. Its penis averages twice the size of its eastern Washington counterpart. In fact, the Mazama pocket gopher has the largest penis of any member of its family.
Wolf Haven’s mounded prairie, like other mounded prairie in the area, as readers may be aware, are embroiled in the ongoing controversy concerning the origin of Mima mounds. Two mammalogists, Walter Dalquest and Victor Scheffer, championed the theory that pocket gophers formed these regularly spaced, dome-shaped mounds. Their hypothesis is still among the most credible. However, there are other, competing hypotheses, that haven’t been totally discounted. One involves primeval flooding of a climax forest. The tree roots anchored soil particles while water eroded away soil between the regularly spaced trees. When the forest died and the trees decayed away, all that was left was the mounds. Another hypothesis resulted from observations of particles on a board subjected to shaking, as in an earthquake. The particles tended to form regularly spaced mounds, similar to the shape and spacing of Mima mounds.
Whatever their origin, the Mima mounds at Wolf Haven appeared, prior to our efforts, to be gopher-free. Soil eruptions were common enough but all of them had the characteristics of mole mounds. At least this was a good sign that the rocky glacial outwash soil was friable enough for a small mammal to burrow in. Additionally, Mazama pocket gophers were well-documented from areas very close by, including the Rocky Prairie Natural Area Preserve, just a mile northwest of Wolf Haven.
The habitat at Wolf Haven is in excellent condition. The Nature Conservancy has been working to restore the mounded prairie at Wolf Haven for over a year, primarily by removing Scot’s broom, both mechanically and chemically. Native grasses and forbs are now thriving in the sun-exposed prairie.
The effort to put gophers on the property started with an opportunity, about a year ago. A development had been proposed for the corner of Rich Road and Yelm Highway. The Washington Department of Fish and Wildlife’s habitat biologist, Debbie Carnevali, wanted the gophers on the site saved. She negotiated an admittedly small set aside. The development would still take out a considerable number of gophers. So, Debbie talked to me, about moving some gophers. Before long, staff of WDFW, TNC, Fort Lewis, and several volunteers, were spending their early morning and evening hours trapping and moving gophers. Before the bulldozers arrived, twenty-four gophers were live-trapped and driven the 15 miles to Wolf Haven. The release procedure was simple: dig a small hole in the ground, set the gopher in it, and hope the animal would continue the digging of its new home.Some did and some wandered off overland.
It wasn’t long before additional developments were proposed in the land of gophers. A 120 acre housing development and 40 acre industrial development were proposed on land south of the Olympia Airport. It was an area that had been logged in 1981, cleared of stumps and converted from mixed forest to cow pasture. The soils were generally deep and soft. Gophers dispersing from the Olympia Airport likely established the new population on this property, a population that appeared to be thriving. Once again, Debbie Carnevali, in her role as habitat biologist, weighed in on the proposed Mazama pocket gopher management plan which was required under the City of Tumwater’s Critical Areas Ordinance. The set asides on this 160 acre landscape would provide for a fraction of the existing population but many would be lost. Knowing that Wolf Haven had capacity to support many more gophers, Debbie worked out another translocation. Because the development was so large, and affected so many gophers, the developers were asked to pay for the trapping and translocation of the gophers. Their contributions made it possible to hire a biologist to work on the trapping and translocation for nearly full time for two months. Contributions of staff time by the Department of Fish and Wildlife and The Nature Conservancy rounded out the project.
It all came together in September of 2006. Mike Walker was hired as the lead trapper. Lindsey Baris, an Americorps employee assigned to The Nature Conservancy, became an indispensable member of the trapping team. A whole host of others participated including the staff at Wolf Haven. This time, some lessons from other fossorial mammal translocations were applied to try to make the transition for the gophers as smooth as possible. Prior to release, a gas-powered soil auger was used to bore out two and half inch diameter holes about two feet deep. Four to six holes were bored in each Mima mound that was to receive a gopher. The gophers, prior to their release, were equipped with a PIT tag (a small, glass-encased microchip injected under the skin of the gopher’s back). Gophers were weighed, sexed, PIT-tagged and placed in front of a pre-drilled hole that had fresh carrots stuffed into it. After the gopher made its way underground, a hardware cloth cap was spiked over the top of the burrow to discourage the gopher from moving off overland, a choice that was believed to be risky for gophers in an unfamiliar land rich with hawks, ravens, and coyotes.
As Thanksgiving Day approaches, the 2006 trapping effort, which began in October, has resulted in 80 Mazama pocket gophers being moved to the new home at Wolf Haven. In March or April, gopher burrows will be opened to the light and a PIT tag reader and racket antenna will be left to read the gopher’s tag when it comes to plug out the intruding light. In this way, we’ll establish a minimum survival rate through the winter period, something that hasn’t been done before. Hopefully, the outcome of this work will be a new Mazama pocket gopher population and significant new knowledge to be applied in future efforts to conserve an often-overlooked part of Washington’s wildlife communities.
