Surveys that have been conducted at Spenceville Wildlife Area (SWA) document the presence of 42 mammals, 160 birds, 12 reptiles, 4 amphibians, and 20 fishes including lamprey and crayfish (Rogers et al. 1996). Most of these species are permanent residents, but some are seasonal migrators such as anadromous fish and various birds including 26 as neotropical species (Rogers et al. 1996).

Birds are present in all habitat types. The Riparian Woodland habitats are critical to Neotropical migrant birds, especially during the fall season. During all seasons, the highest diversities and densities of birds are found in or near dense streamside vegetation (Rogers et al. 1996).

Of the 43 mammals at SWA, 9 are carnivora. The river otter has been documented in the last 2 years. The Columbian black-tailed deer population is estimated at 150-220 animals and wild pigs occur occasionally (Rogers et al. 1996). Seventeen rodent species are residents of the wildlife area, the black-tailed jackrabbit the most common. Ten species of bats also reside and 2 of those species Townsend's big-eared bat and the pallid bat, are Species of Special Concern (Rogers et al. 1996). The Pacific tree frog is the most common amphibian of SWA.

Spenceville Wildlife Area has a very diverse reptile population. The Western pond turtle is a Species of Special concern and is common to the reserve. Gopher snakes and rattlesnakes are the most commonly observed snakes (Rogers et al. 1996).

The primary fishery resource of the SWA are largemouth bass, bluegill sunfish, redear sunfish, and channel catfish. Brown and rainbow trout occur in colder habitats along Dry Creek although they are not numerous. Fall chinook salmon and steelhead are also present in Dry Creek (Rogers 1997) entering by ladder over a small dam on Beale Air Force Base, and salmon fry have been stocked in Dry Creek in recent years (Rogers et al. 1996). The passage of Anadromous fish into Dry Creek depends on adequate water flows existent when adult fish are present and migrating (Rogers et al. 1996).


Four state and/or federally listed endangered and threatened wildlife species have been recorded or are expected to exist at Spenceville Wildlife Area. The bald eagle, a California Endangered Species, is a winter visitor to the area. Another California Endangered Species, the willow flycatcher, also utilizes the area of Dry Creek and its tributaries as migration corridors in the late spring and late summer. The California black rail, a California Threatened Species, has been found nesting at SWA. Blue-elderberry bushes are documented at the wildlife area and it is assumed that the Federally Threatened valley elderberry longhorn beetle also exists (Rogers et al. 1996). Four of the 17 birds listed as California species of Special Concern have been seen using the reserve and an additional 4 are suspected of nesting there (Rogers et al. 1996).



Coyote (Canis latrans) Though the coyote resembles a collie-sized dog, it moves across the hillsides with an independence and grace that clearly identifies it as wild. The valley subspecies coyote differs from the mountain coyote in that it is smaller and has a lighter buff-gray to rusty fur color. For shelter, it finds a natural den, enlarges a rodent burrow or digs its own hole. It gives birth in spring or early-summer to 3 to 11 furred young. Both parents feed the pups but by fall they are grown, and the family members scatter to begin life on their own. Coyotes are omnivorous, eating manzanita berries, and other plants, various rodents, including mice, gophers and squirrels, an occasional bird, or even deer killed by a mountain lion. This wide range of diet, their lack of predators and their wily adaptability have made them one of the few animals to increase in number and extend their range, in spite of western man's attempt to eradicate them.

Wildcat (Lynx rufus) Also called Bobcat, because of its short tail, the wildcat measures up to about 24 inches in height. Its soft fur is a light reddish brown in summer and grayish in winter with white undersides spotted with black. Its bobbed tail is 4 to 6 inches and is white below and black tipped. Active by day, this feline can climb trees easily to raid nests of eggs, although it feeds mainly on a diet of rabbits, rodents (especially ground squirrels) and wood rats. Though usually silent, it can scream much louder than a house cat. Its shorter stance make it better equipped for the grassland and open country than its relative the mountain lion, which usually keeps to the higher trails following the Mule Deer. The Wildcat keeps the woodlands and grasslands in balance and is an exceptionally valuable environmental component.

Gray Fox (Urocyon cinero-argenteus) The coat of the Gray Fox is steel gray with a stripe down the back, and the back of the neck and legs are a reddish brown. They are primarily found in brushhy foothills and wooded areas. The Gray Fox is a difficult species to find due to its shy nature. They feed on small rodents, fruit, birds, and eggs. It is an especially agile creature that is capable of climbing a tree.

Ringtail (Bassariscus astutus) is smaller than a raccoon. The elusive ringtail weighs approximately 2 pounds. It is slender with a tapered muzzle and is at home in rocky and wooded places in the foothills and valley riparian areas. It is omnivorous, feeding on berries, nuts, invertebrates, and eggs. Manzanita and Toyon berries are a favorite food. The Ringtail is an excellent climber and uses its bushy tail for balance. It sleeps high in a tree during the day time hours and only leaves the tree when it is completely dark. Often referred to as "miners cats", they were kept by early settlers to keep the mice populations down.

Striped Skunk

Spotted Skunk

Long-tailed Weasel

River otter



Mule Deer (Odocooileus hemionus) The Mule deer gets its name from its very large ears. The bucks start growing new antlers each spring and then shed them in winter. These animals like a variety of vegetation types in which to browse on and find cover. They prefer tender new growth of various shrubs to graze and also enjoy mushrooms, which they dig for under the surface of the soil.

Wild Pig


California ground squirrel

Golden-mantled ground squirrel



Meadow mouse

Western harvest mouse

House mouse

Botta's pocket gopher

Little pocket mouse

Heerman's kangaroo mouse

Deer mouse

Brush mouse

Pinon mouse

Dusky-footed woodrat

California vole

Back rat


Black-tailed jackrabbit

Desert cottontail

Brush rabbit


Brazilian Free-tailed bat (Tadarida brasiliensis) This bat occurs throughout California and prefers woodland, shrubland, and grassland habitats. It uses echolocation (sonar) to hunt for small flying insects such as moths. This species is a fast flyer and averages 25 miles per hour when traveling to and from roosting sites. Hibernation and roosting occurs in caves, mine tunnels, and crevices. Most females have only one young in a litter, but females will nurse any needy young. Life expectancy is approximately 6-8 years.

Yuma myotis

California myotis

Small-footed myotis

Western pipistrelle

Big brown bat

Red bat

Hoary bat

Townsend's big-eared bat

Pallid bat


Broad-footed mole


Virginia opossum


Warmwater game fish

Largemouth bass

Smallmouth bass

Florida bluegill

Redear sunfish

Green sunfish

Channel catfish

Brown bullhead

Coldwater Game Fish

Chinook or King Salmon (Onchorynchus tshawytscha) Onchorynchus means "hooked jaw" describing the male salmon's physical changes he undergoes prior to mating. His jaw grows and hooks to the point he can no longer close his mouth. Salmon return to Dry Creek each fall, swimming up stream to where they were hatched. Salmon may reach large sizes, with the all tackle record for California at 88 pounds. Although the run on Dry Creek represents a small number compared to that of the total Sacramento River run, it represents a unique resource as a part of the overall salmon run of Fall Chinook that is threatened as its numbers dwindle.

Steelhead rainbow trout

Rainbow trout

Brown trout

Non-game fish: native

California Roach (Hespereroleucus symmetricus) A member of the true "minnow family", this small fish reaches only 5 inches. The young of many fish species are mistakenly referred to as "minnows' because they are small. True minnows, often smaller fish species, may be overlooked by the casual observer. These real minnows fill a specific part of the ecology of the streams in Spenceville Wildlife Area providing food for larger animals.

Sacramento squawfish (Ptychocheilus grandis) Also a member of the minnow family, the Sacramento Squawfish mocks the minnow stereotype, reaching lengths up to 4 feet. Specimens in Dry Creek and other Spenceville Creeks would likely to be smaller, but could easily reach 2 feet. Squawfish are carnivorous, too, undoing the minnow myth.

Riffle sculpin (Cottus gulosus) A small fish, 3-5 inches that dwells on the bottom of clear running creeks. They have broad flattened heads, and seem to "hop" along the bottom of the creek.

Western sucker

California roach

Non-game fish; introduced

Golden shiner

Fathead minnow

Mosquito fish

Fish-like species

Pacific Lamprey (Lampetra tridentata) Another unusual fish found in the Spenceville area is the Pacific Lamprey. One of the jawless fishes, it also has no scales. The young even lack a sucking disk and eyes.

Pacific lamprey



Pacific Tree Frog (Hyla regilla) The Pacific Tree Frog inhabits moist areas and ponds from the valley floor to mountain top, and are mostly active between late afternoon and midnight. By using the suction discs on each of their toes, they can climb almost any vertical surface. Although they are mainly land dwellers, they will venture into trees in search of insects for food. Insects, along with slugs, spiders, centipedes, and earthworms make up the diet of the Pacific Tree Frog. Their characteristic choruses have given them the nickname "spring peepers".

California Newt (Taricha torosa) The California Newt, with its dark brown back and fiery orange belly, is most often seen in foothill streams. Their concentration in moist areas is due to their need for moisture. They often find refuge in burrows, under rotten logs, or under rocks. They can also be observed at the bottom of shallow pools of water where they retreat for breeding. The fan like gills around the neck enable the newt to live under water until it reaches its terrestrial stage. Their diet consists of snails, slugs, earthworms, sow bugs, and insects.

Western toad




Western Pond Turtle (Clemmys marmorata) This California native turtle is associated with permanent or nearly permanent water sources in a wide variety of habitat types such as ponds, streams, and rivers. It is omnivorous, feeding on aquatic plants, invertebrates, fishes, and frogs. This turtle will leave the water to bask in the sun or lay eggs, but never ventures far on land. In the winter it hibernates in the mud of shallow, quiet water.



Western Whiptail (Cnemidophorus tigris) Western whiptails are active diurnal lizards that inhabit a wide variety of habitat types. They are most likely to be found foraging in woodlands and streamsides on spiders and insects. They will occasionally stalk larger prey items such as grasshoppers. Their diet may change seasonally to reflect the abundance of prey. When running, the tail of this appropriately named lizard, lashes about. It may also run on its hind legs only.

Northwestern fence lizard

Northern brown skink


Ringneck snake (Diadophus punctatus) A relatively uncommon somewhat secretive snake that spends most of its time in open, moist, and moderately rocky areas under rocks or logs. Ringnecks forage for food on or under the surface of objects taking frogs, earthworms, lizards, and other small snakes. When alarmed, this snake may coil and show its bright red undersurface.

Mountain garter snake

Valley garter snake

California striped racer

Western yellow-bellied racer

Gopher snake

Common kingsnake

Northern pacific rattlesnake