In the past 60 days, the ponds, reservoirs and wildlife habitat in the foothills of Northern California have gone from famine to feast.

The stage is set this spring for a far-reaching rebirth and expansion of the populations of fish (from bass to catfish to bluegill), wildlife (from squirrels to deer to wild hogs) and birds (from songbirds to ducks to eagles).

The amount of water out there, and what it means for spring, is mind-bending.

California has 6,000 small lakes and farm ponds, including about 200 in the Bay Area foothills, according to the Department of Water Resources, plus hundreds more at golf courses. Virtually all of them have filled. The wild grass is so bright green (and full of water) that it looks electric on blue-sky days. The coming wildflower season looks like a sure thing.

One testament to the rebirth at hand is at Red Bank Ranch, where owner Brian Riley manages more than 18,000 acres of foothill uplands for wildlife habitat. His properties are in remote Tehama County above the Sacramento Valley west of Red Bluff.

At midweek, Riley put his rig in 4-wheel-drive and showed off how the winter rain has transformed wildlife habitat across the foothills.

Saturated soils: The first thing you notice is how rain on top of saturated soil has created ephemeral pools — that is, temporary pools of water, often amid oaks, in areas that are dry most of the year. This creates sensational habitat for breeding frogs, toads and salamanders. It also creates nesting habitat for waterfowl, especially mallards and Canada geese; they nest in dry areas, such as tules, grass or weeds, and after the hatch will lead their young to nearby water.

Neon green: In spring, when the wild grasses, weeds and wildflowers erupt — and wild mustard is already booming across the Bay Area foothills — they will provide seeds for an array of songbirds, plus fresh vegetation for this spring’s crop of fawns and other wildlife.

Ponds flooded: The ponds are often over the banks and in some cases have put oak trees under water. At one pond, Riley showed how a pond had flooded over a ranch road and poured water into a wide depression that created a new small pond. In ponds, fish populations and their spawning success, especially for bass, catfish and bluegill, often rise and fall according to how much water is available.

How it works: The “balance of nature” has little to do with the predator-prey relationship, but rather is based on the carrying capacity of habitat. Each habitat provides enough food, water and cover to support so many fish, wildlife or birds. The populations will rise and fall according to the carrying capacity. This spring will see a rise in carrying capacity, with so much water, more food and more cover.

Riley noted that wildlife survival rates are linked directly to nutrition. “I’m thinking we’ll have big crops of wild hogs and deer this spring,” he said.

Great news for delta

For those who roam around California, one of the most stunning sights is the before-and-after scenario at giant San Luis Reservoir, the fifth-largest reservoir in the state. San Luis is not fed by storm runoff, but by water diverted from the San Joaquin-Sacramento River Delta, which is then sent to points south. San Luis looked like a huge crater in the foothills last year when it was dropped to 10 percent full, its lowest level in 27 years. On Saturday, it hit 90 percent full, great news for delta fish. In the spring, when endangered winter-run salmon migrate through the delta and often when striped bass spawn, the delta pumps can be slowed or shut down to allow higher survival rates. At the same time, farmers in the San Joaquin Valley can instead take water out of a full San Luis. Everybody wins. There are several reservoirs that have gone from empty to full.

Weather winners

Nacimiento: Lake Nacimiento in San Luis Obispo County, 17 miles long with great fishing for white bass and largemouth bass in spring and with water sports in summer, has looked something like a dust bowl the past few years as it hovered around 20 percent full. It was up to 86 percent full Saturday, so high for mid-February that releases were started to maintain space for flood control.

Indian Valley: Years ago when full, Indian Valley Reservoir, north of Highway 20 in remote Lake County, was one of California’s best bass lakes (and good for kokanee, too), with miles of stickups from submerged trees that provided habitat. Primitive campsites, too. It’s been at 5 percent for years and off the radar. It was up to 63 percent full as of Friday, 106 percent of normal for the date, and set for a comeback.

Don Pedro: In recent years, many driving to Yosemite on Highway 120 and past the upper end of Don Pedro Reservoir in the Sierra foothills were shocked at the low water levels and exposed shoreline. It hit 97 percent full Saturday, and the Bureau of Reclamation started dumping water.

Shasta: Giant Shasta Lake, the state’s largest reservoir, was 82 percent full at the end of January when water managers released 10 feet of water — down to 78 percent — to create space to collect potential floodwaters. Then, four days of rain or snow, with the Upper Sacramento River flow rising over 30,0000 cubic feet per second and flooding Dunsmuir on Thursday night, brought the lake right back up, eight feet overnight, to 96 percent on Saturday. For Sunday, releases were projected to be raised to 70,000 cubic feet per second.

Rain, snow races

Rain: A state weather gauge at Four Trees in Plumas National Forest on the Feather River watershed emerged in first place for total rainfall for the season reported Saturday with 117.02 inches. Others that hit 100 last week include Stouts Meadow on the Upper McCloud River, 115.76; Venado on the Russian River, 113.30; Miranda on the South Fork Eel River, 106.34; and Pit River No. 5 Powerhouse above Shasta Lake, 109.51.

Snow: Sugar Bowl, located off historic U.S. 40 (off Interstate 80 near Donner Summit) surpassed 500 inches of snowfall for the season (536 inches as of Saturday), the highest reported in California. On Saturday at Mammoth Mountain, at its 11,000-foot ridge in the Minarets, the snowpack, or base depth, was measured at a verifiable 340 inches, that is, 28 feet, 4 inches.

Mr. Sturgy

McNear’s Pier: Massive rain runoff has turned San Pablo Bay into more freshwater than saltwater, helping attract large numbers of sturgeon to the China Camp area off San Rafael. At McNear’s Pier over Super Bowl weekend, despite a howling storm, few anglers and lost fish, they still caught 16 sturgeon, reported Keith Fraser at Loch Lomond Live Bait. “Never heard of anything like it.”

Tom Stienstra is The Chronicle’s outdoor writer. E-mail: tstienstra@sfchronicle.com Twitter: @StienstraTom