There are a handful of mountain locations I visit nearly every year. There is a tension between visiting known sites with a good track record and trying to explore new ones. As late spring approaches, the temperatures rise and bird diversity in the Sacramento Valley drops, and the urge to visit a few of my favorite places in the Sierra is impossible to resist. Because I live near the Hwy 50 corridor, most of these locations are easily accessed from there, so depending on where you live, your list of favorites is likely to be different. (More information on different sites can be found on the DIY Field Trips page under the recommendations for June, July, and August or in the Foothills and Sierra Nevada section of the Birding Locations pages.)
Granite Springs Rd off Ice House Rd is a great place to see a nice mix of mid-elevation Sierran species. This area is best visited in mid-May to June, but will have some activity throughout the summer. As with everywhere this year, the season is advanced with early snowmelt (from a much reduced snowpack). The most productive area is about 3.5 miles in from Ice House Rd, near the spring, with brushy hillsides and standing snags from the Fred's Fire. It is especially good for Nashville and MacGillivray's warblers. The very different looking but similar sounding Thick-billed Fox Sparrows and Green-tailed Towhees are usually pretty easy to find here. The towhee's song is usually buzzier and not quite as musical; the towhee's call sounds like a cat's mew, while the Fox Sparrow's sounds like the sharp chip of a California Towhee (unlike the loud smack of the northerly-breeding Fox Sparrows we have around Sacramento in winter). In recent years, Lewis's Woodpeckers have nested in snags in the vicinity of the springs. Hearing the "quark" of Mountain Quail is easy, but seeing them usually takes a few visits and a little luck. A full write-up can be found under Birding Locations on the SAS website.
Depending on the year, June or July and beyond is a great time to visit the Wright's Lake area. The mountains are among the prettiest in the north-central Sierra, and Wright's Lake has an excellent track record for Black-backed Woodpecker and Pine Grosbeak, among the more expected species. I typically walk the road that goes past the cabins on the south side of the lake and a portion of the trails to the east that lead to Twin, Island, Grouse, and Smith lakes. Listen for Lincoln's Sparrows singing in the marshy areas, and Spotted Sandpipers are usually somewhere along the shore of Wright's Lake.
One of the most dramatic locations within two hours of Sacramento is Winnemucca Lake under the cliffs of Round Top (the "pretty meter" maxes out at 10). I typically walk from Woods Lake to Lake Winnemucca, sometimes out and back, and sometimes as a loop past Round Top Lake. Red Crossbills and Rock Wrens are often found, along with species mentioned above (occasionally Pine Grosbeak). Gray-crowned Rosy-Finches are sometimes found, but I have never been so lucky (around 20 trips, including two to the top of Round Top). If you have time to drive 30 minutes farther east, the little park in Markleeville along the creek, as well as Airport and Diamond Valley roads east of Hwy 89, are definitely worth repeated visits. Before long, migrant shorebirds will be coming back through the Valley, followed closely by the migrant songbirds, but an escape to the mountains sure helps shake the summer doldrums.