Think of the parks as nature's zoo. There are no cages, no man-made habitats -- just wide-open spaces with enough room for more than 200 species of mammals and birds, some of which are described below.

Birds

The Sierra Nevada is a bird-watcher's paradise. Each year, 135 species visit Yosemite Valley alone. The most treasured of the area's feathered friends include the great horned owl, the peregrine falcon, and the California condor, all of which send bird-watchers into ornithological ecstasy.

You're more likely to hear the great horned owl than see one. Its hoots sound like sonar, but since it is nocturnal, it's difficult to spot. If you happen to hear it, try to locate its branch first, and then the bird: It has large tufts of feathers near both ears. But don't get disheartened if you search in vain -- these birds are great ventriloquists. You'll have more luck observing a pair of nesting peregrine falcons on El Capitan or Glacier Point, although you'll need binoculars. For several years now, a number of pairs have made this their own personal day-care center, hatching and raising their young on narrow ledges before beginning flight instruction. One of four falcon species in the park, the peregrine falcon is marked by a hood of dark feathers from head to back, contrasting against lighter ones underneath. This bird is a wizard in flight, reaching speeds of up to 200 mph mid-dive. It was recently removed from the endangered species list.

Still endangered is the California condor, the largest land bird in North America, with a 9-foot wingspan. The birds are able to glide 10 miles at a time without flapping their wings. Keen eyesight allows them to spot a dead animal carcass from miles away. Their numbers dropped below 40 in 1975, due to pesticide use and the loss of habitat to building. A pair of condors can raise only one young every 2 years. In the 1980s, the remaining birds were captured and placed in zoos, where the young were hand-reared. Then some of the adolescent birds were released into the wild and have been seen occasionally in Kings Canyon. Today about 200 California condors exist in the wild.

In both Yosemite and Sequoia & Kings Canyon, the birds you're most likely to see are the American robin, Steller's jay, acorn woodpecker, northern flicker, band-tailed pigeon, two varieties of blackbird, sparrow, swift, American dipper, belted kingfisher, duck, warbler, brown creeper, mountain chickadee, and red-breasted and white-breasted nuthatches. Yosemite Valley is a great place to see many of these species because its environment includes streambeds, rivers, forest, and meadowlands, often within the space of a city block. A stroll anywhere along the Merced River should take you within visual distance of all of these birds, whose habitats include the water, meadows, and adjacent forests.

A reddish-orange breast easily distinguishes the American robin. These are the same birds you can see back home throughout much of North America, in suburbs and backyards, building cup-shaped nests on windowsills or the ledges of buildings. Before the bird adapted to urban living, it preferred a woodland habitat. It has long been considered a harbinger of spring, but in reality some of these birds stay put year-round. The Steller's jay is one of nature's more annoying birds. Unfazed by humans, it is a bold beggar, landing on picnic tables and elsewhere near food, while letting loose a screech that could wake the dead. The Steller's jay is bright blue, with a dark head and prominent crest. This bird is also capable of a beautiful soft warble.

Like the Steller's jay, you're likely to hear the woodpecker before you see it -- listen for its methodical rata-tat-tat. Woodpeckers can also emit a startling call that sounds like "wack-up." Woodpeckers are distinguished by black-and-white markings and a red crown, with an occasional bit of yellow. The northern flicker is also a woodpecker -- look for a brown-feathered bird clinging to the side of a tree. Its wings have a reddish tinge and it sports a red mustache. This bird prefers to feed on the ground, where it searches for ants. Band-tailed pigeons are similar to their city-dwelling cousins but prefer tall forest trees to buildings.

In meadowlands, you will likely see sparrows, the black-headed grosbeak, the uncommon western tanager -- a bird with fluorescent feathers -- and two varieties of blackbird. The Brewer's blackbird and the red-winged blackbird both make their home here. Brewer's blackbirds nest in trees, while their red-winged relatives prefer slightly marshy areas. Red-winged males have distinctive red patches on their wings. The Brewer's blackbird is, well, black, and females of either variety are drab in comparison to the males. Sparrows are small singing birds, streaked by brown feathers and with cone-shaped beaks. Their babies leave the nest 10 days after birth. The black-headed grosbeak has black, white, and orange markings, and a distinctive beak used for cracking seeds. Its soft, lyrical warble is music compared to those of other valley dwellers, and this bird is considered a sure sign of spring. The easy-to-spot western tanager is bright yellow with a reddish-orange head and is frequently observed in Yosemite Valley during spring and summer.

If you're near moving water, you might search for American dippers, belted kingfishers, ducks, and warblers. The American dipper is notable more for its flying acrobatics than for its nondescript color. The bird flies headfirst into the river to walk upstream along the bottom, clinging to rocks in its search for food. The belted kingfisher is a highly visible blue bird that flies low over water in search of prey. You may see it perched above the water, clinging to branches and underbrush, and keeping a watchful eye out for insects and fish. It has a reddish band on its chest and a noticeable crest up top. The call of the kingfisher is distinctive: loud, rattling, and clicking. Warblers are often called the butterflies of the bird world. They are small, brightly colored, and move with gravity-defying ease. Contrary to their name, warblers are undistinguished singers, but they're great at collecting insects.

In the forests live brown creepers, mountain chickadees, and red- and white-breasted nuthatches. The brown creeper is difficult to spot because of the camouflage feathers that disguise it among tree trunks. Small, with a slender, curved beak, the creeper usually begins foraging for insects at the base of a tree and works its way up, clinging to the bark with razor-sharp claws. The mountain chickadee is another songbird with a delightful melody that sounds like "chickadee-dee-dee." These tiny, friendly, hyperactive birds have dark caps and bibs, a gray or brown back, and a distinctive white eyebrow. They nest in woodpecker holes or other small tree holes. Nuthatches are the birds you'll see walking headfirst down a tree trunk -- no simple feat. Also called upside-down birds, the red-breasted and white-breasted versions are aptly described by their names. They are partial to abandoned woodpecker holes.

And let's not forget the swift, almost always found in flight above Yosemite Valley. These birds spend more time air-bound than any other land bird. When they do stop, they cling to vertical surfaces because their tiny feet are unsuitable for perches. Look up to see swifts flying between Yosemite's great granite walls. Both sexes look alike, and colors run from drab grays and browns to black and white.

In the Wawona region south of Yosemite Valley, you'll find the bushtit and wrentit, scrub jay, California thrasher, yellow warbler, lesser goldfinch, barn swallow, and ash-throated and rare willow flycatchers. The yellow warbler is the more colorful version of the warbler described above. Swallows are streamlined-looking birds with long, pointed wings. Swift in flight, they eat and drink on the fly. All are migratory, and some travel thousands of miles to the Tropics each winter. Flycatchers are better known for their insect-hunting abilities than for distinctive markings. The willow flycatcher is a threatened species and has gray, brown, and olive plumage. All flycatchers are very territorial. Goldfinches, sometimes referred to as wild canaries, are gregarious birds, with bright colors and cheerful songs.

Bushtits spend most of the year in flocks of about 20, constantly twittering at each other with a soft, lisping call. These acrobatic fliers are small, grayish birds with tiny bills. Wrentits are secretive birds -- hard to see but easy to hear. They seldom venture far from home and prefer to live in chaparral or scrub thickets. Once mated, they form devoted pairs, constantly pruning and preening each other. When seen close together, they resemble a single ball of gray fluff. The California thrasher is one of several thrasher species, all of which have long tails and nest in low thickets. They forage on the ground and are accomplished singers, though not as notable as their distant cousins, the mockingbird and catbird.

The high country of Yosemite and Sequoia & Kings Canyon attracts dozens more birds, drawn by altitude and mountain meadows, including the dark-eyed junco, kestrel, red-tailed hawk, killdeer, Williamson's sapsucker, Clark's nutcracker, and ptarmigan.

Juncos, often referred to as snowbirds, are common visitors to bird feeders. Small and friendly, these birds resemble the sparrow, which also frequents this region. But the dark-eyed junco has a pink bill, white-to-bluish underbelly, and dark feathers from the crown down its back, and can usually be seen hopping along the ground in search of food. The kestrel is the smallest species of falcon. Like the falcon, it kills prey with a sharp bite to the neck, as opposed to hawks, which kill with their sharp claws. The red-tailed hawk, equipped with broad, rounded wings and a fan-shaped tail, soars effortlessly, using its keen eyesight to scan the area below for prey. The killdeer -- named for its shrill call, is a performer, often feigning a broken wing to ward intruders off when they venture too near its nest. And no wonder -- nests are little more than a shallow depression in the ground lined with pebbles. Adult killdeer have two black bands across their throats, while chicks have one.

Sapsuckers are specialized woodpeckers that extract the sap from trees with their brush-tipped tongues after drilling holes with their beaks. They also eat insects attracted to the sap. The Williamson's sapsucker strongly resembles the northern flicker described above, minus the red mustache. Nutcrackers are bold cousins of the crow family. Clark's nutcrackers specialize in prying seeds from pine cones and make forests their stamping grounds. In late summer and fall, the birds begin hoarding seeds for winter, tucking them in a pouch under their tongue during transport to slopes, where they poke holes in the ground and bury their treasure. A single nutcracker can hide 30,000 seeds. More remarkable is the fact that they remember where the stock is buried by the position of nearby landmarks, even when the ground is covered with snow. Clark's nutcracker resembles a crow, with a gray head and body and black wings tipped with white.

Finally, the ptarmigan is a unique bird, well adapted to changing seasons in cold climates. These small, stocky grouse have mottled brown feathers in summer to help camouflage them against the rocky mountaintops where they live, but the feathers turn pure white in winter to match the snow. Like all grouse, ptarmigans have feathered legs, and in winter their feet are also covered with feathers. During the spring mating season, males sport a vibrant red comb and strut in short flights while cackling, all to attract a mate.

In addition to the above birds, Hammond's flycatcher, Cassin's finch, common flicker, pine sparrow, chipping sparrow, white-crowned sparrow, and violet-green swallow are all prevalent in the high country.

Mammals

Mammals in these parks are not seen as often as birds, but for some reason they're a lot more fun to spot. Most common are the mule deer, raccoon, squirrel, chipmunk, fox, coyote, and black bear. At higher elevations, you may also see Belding ground squirrels and Douglas's squirrels, yellow-bellied marmots, pikas, pine martens, badgers, mountain lions, bobcats, porcupines, long-tailed weasels, striped and spotted skunks, and northern water shrew.

Mule deer are most frequently spotted grazing in meadows at dawn and dusk. Although they seem gentle enough, mule deer should be treated with the same reverence accorded any wild animal: Give them a wide berth and, of course, refrain from feeding them. Many injuries have been recorded against humans who attempt to get close or feed them. The mule deer is named for its large, mulelike ears, and adults can weigh up to 200 pounds, surviving on a mix of grasses, leaves, tender twigs, and herbs. Males grow antlers for use during the mating season. And no, it is not true that the age of a male deer can be gauged by counting the points on its antlers.

A variety of members of the squirrel family reside in this region, including chipmunks and marmots. The most common is the California gray squirrel, often seen in trees with its gray coat and bushy tail. The California ground squirrel is a brown animal with white speckles that prefers living in burrows. The Sierra chickaree is a reddish-colored tree squirrel that chews on pine cones and frequently makes a squeaking noise. Douglas's squirrel, common in Sequoia, is an olive-to-rust or gray color, with a reddish underbelly. At higher elevations, the Belding ground squirrel is most easily distinguished when it's seated -- its erect posture resembles a stake driven into the ground. There are at least five different varieties of chipmunks in this region. Smaller than squirrels, they're quick and love to chatter, especially when scolding those who venture too near. Chipmunks range in color from reddish-brown to brownish-gray, and all varieties have four stripes running the length of their backs.

At higher elevations, you'll find the yellow-bellied marmot. Resembling woodchucks, they regularly sunbathe and can tease visitors into believing they are tame. They're not. Adult marmots appear yellowish-brown, weigh up to 5 pounds, reach 15 to 18 inches in length, emit a high-pitched shrill as a warning, and live beneath rock piles or tree roots.

The porcupine is a unique rodent. These short, stock-legged creatures are covered from head to toe with quills that detach at the touch, piercing whoever or whatever touches them. Each animal carries about 30,000 quills that serve as a serious deterrent to all but the stupidest predators. Porcupines sleep during the day and forage at night, curling into a ball when approached by a would-be predator. In spring, females produce one offspring, which is born with soft quills (thankfully) that harden within minutes.

Pikas look like a cross between a rodent and a hare, and actually are distant relatives of the rabbit family. Pikas have oversize ears, although they're proportionately much smaller than those found on their cousins, and live in colonies above the tree line throughout the West. They scamper over rocks and emit a high-pitched squeal whenever a predator is sighted.

Raccoons are considered pests in suburbia, but in the wild they are shy nocturnal animals, easily spotted by their ringed tails and the appearance of a black mask across their eyes. Some are no bigger than a large house cat, but males can grow to be 3 feet in length and may weigh more than 40 pounds. These animals are adaptive, eating everything from fish and small rodents to fruit, nuts, and earthworms.

The parks contain a large number of weasel-family members, including badgers, martens, skunks, and what most people know as weasels. The long-tailed weasel can reach 16 inches in length. Usually brown with a white underbelly, in winter it can turn all white, while retaining a black tip to its tail. The badger and marten are distant cousins of the weasel. Badgers can reach up to 2 feet in length and weigh up to 25 pounds. This heavy, short-legged animal has black feet, black-and-white face markings, and coarse yellowish-gray fur. The pine marten is a fast, agile climber preferring high mountain forests. It is sometimes mistaken for a squirrel as it bounds from limb to limb, probably chasing a red squirrel, its favorite dinner. If you're not familiar with skunks, consider yourself fortunate. Best known for the awful scent they release when scared or under attack, skunks are otherwise cute, fluffy animals with distinctive black-and-white markings. Most common is the striped skunk, its white-on-black stripe running from nose to tail tip. The spotted skunk is rarer but lives in Sequoia & Kings Canyon National Parks.

Foxes, coyotes, black bears, bobcats, and mountain lions also inhabit this region. Most avoid crowds and shun humans, but coyotes and black bears are frequently spotted in the middle of Yosemite Valley, where they rely on the misguided benevolence of humans who feed them. Coyotes resemble dogs, with long gray fur and bushy tails. They feed primarily on small rodents and the occasional fawn, and grow to weigh between 25 and 30 pounds. One of the coyote's most distinctive traits is its howl, a long, haunting call that some consider frightening. The black bear is the largest mammal in these parks. It is often confused with the grizzly bear, which is much larger and much more fearsome. Incidents involving black bears usually occur due to improper food storage. Never feed bears, and by no means should you walk toward them. Observe from a safe distance. Despite their names, black bears can also be brown, blond, and cinnamon colored. Adult black bears grow to 250 to 500 pounds, and larger ones have been recorded. They are omnivores, eating both meat and vegetation, and they've proved very adaptable to hot dogs, hamburgers, and cookies. Unfortunately, once they become dependent on human food, these bears can prove bold and determined to continue their new diet. At this point, they must be trapped and killed by park rangers. Therefore, you must follow food-storage regulations.

Foxes, bobcats, and mountain lions are less frequently spotted in the parks, especially the latter two. The most common fox is the gray fox, with its bushy tail, reddish-gray coat, and black paws. Members of the dog family, they look larger than they actually are -- average weight is 10 pounds. Foxes are skillful hunters and eat rodents, berries, rabbits, and insects. Bobcats inhabit Sequoia & Kings Canyon National Parks. They are nocturnal and resemble a large cat, with a black-spotted tawny coat. The "bob" refers to their stub of a tail, a feature shared with their close relative, the lynx. Adults max out at about 20 pounds, and while much smaller than the next predator on our list, bobcats can kill deer many times their size. They are masters of the slow hunt -- methodical, solitary, and patient. Mountain lions shy away from any human contact, so seeing one is extremely rare. These large cats can reach 5 feet in length. Their fur ranges from tawny to gray, their tails tipped with black. Solitary predators who prefer elk and deer, in lean times they'll settle for a porcupine or skunk.

Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.