Knoxville Wildlife Area is a very popular location for hunters targeting upland game birds, black-tailed deer and wild pig. It even offers limited waterfowl hunting opportunity. Knoxville consists of 21,000 acres dominated by oak woodlands with expanse stands of chaparral. Several valleys lie throughout the wildlife area with the majority along the riparian flats of Eticuera creek, providing open grasslands.
Under natural conditions these grasslands provide critical nesting, brooding, and foraging habitat for several upland game bird species, including California quail and wild turkeys. The tall grass also serves as forage and much needed fawning cover for the resident black-tailed deer herd. Unfortunately, as with many of California’s rural lands, the majority of these valleys no longer contain natural grasslands. Instead they are infested with invasive exotic plant species. The two main culprits being yellow star-thistle (Centaurea solstitialis) and medusa head (Taeniatherum caput-medusae).
Yellow star-thistle is a very aggressive invasive. It contains a large taproot extending 2-3 feet below the soil surface. This allows yellow star-thistle to out-compete native annual species and dominate entire sections of the landscape. The recent drought has amplified yellow star-thistle ‘s stronghold in many areas.
Medusa head is also a strong aggressor that out-competes native annuals. Once established, medusa head can create densities of 1,000-2,000 plants per square meter, not only eliminating native grasses and forbs but also creating high fire danger.
Yellow star-thistle and medusa head serve very little wildlife value due to their homogeneous thick cover and unpalatable plant bodies. Due to the needle-like stickers on yellow star-thistle’s flowering body and the burrowing seed heads of medusa head, these plants also create a hunter access issue. Medusa head’s seed heads can be detrimental to the eyes and noses of hunting dogs, so most hunters avoid these areas for the safety of their hunting companion. In a similar sense, deer season on Knoxville occurs in the very warm months of July, August, and September, and hunters tend to wear light and breathable clothing. Yellow star-thistle ‘s needle-like stickers penetrate light clothing with ease, leaving deer hunters avoiding dense patches. Yellow star-thistle and medusa head are bad news for wildlife and hunters alike.
So, the National Wild Turkey Federation decided to team up with the California Department of Fish and Wildlife, CAL FIRE, and the California Deer Association to convert 60 acres of invasive yellow star-thistle and medusa head back into native grasses and forbs.
Work began in the summer of 2016 when CAL FIRE lit off a prescribed burn over the entire unit to wipe the area clean from old thatch and vegetation. That was then followed up by a few more rounds of site prep in the fall of 2016 and the spring of 2017. In the fall of 2017 the California Department of Fish and Wildlife planted the perimeter of the unit with a cereal grain to act as a buffer to the surrounding invasive plant species, as well as to provide a rich source of food for wildlife. The inner portion of the unit was planted with native seed in December of 2017, provided by a $30,000 grant to the National Wild Turkey Federation from the California Upland Game Bird Account, and an $8,000 grant from the California Deer Association.
The National Wild Turkey Federation District Biologist, Kevin Vella, went to check in on the site just a few days prior to the spring turkey season and found a spectacular sight! Toward the back of the unit was a flock of eleven wild turkeys, including one tom in full strut, three jakes, and seven hens. Toward the front of the unit were five more wild turkeys including one tom, one jake, and 3 hens. Several different pairs of Canada geese courting and looking for suitable nesting locations, two separate coveys of California quail, and several flocks of mourning dove flying from oak tree to oak tree. It was a game bird paradise!
A big thank you goes out to California Department of Fish and Wildlife Area Wildlife Biologist, Stacy Martinelli and Habitat Manager Cris Crecelius for making this project happen.
The National Wild Turkey Federation will continue to monitor this site and assist Knoxville Wildlife Area in maintaining this unit.