To my surprise, the large parking lot along Castle Rock Rd., Walnut Creek, opposite the equestrian centers,
was open at 6:30am.
I walked through the recreation facility, then up into Diablo Foothills Regional Park to the state park boundary, and
about a quarter mile beyond. Activity and song were abundant. I observed several Western Bluebird juveniles, fully fledged and still quite
streaked, begging and being fed. Likewise with numerous Dark-eyed Juncos and their young.
Activity appeared to peak around 8am, then tapered off until ~9:30, when temperatures abruptly began their rise. Overall, the atmosphere
was still, allowing bird song to peel through.
Here's a partial list of this morning's species, both seen and heard.
Cassin's Vireo (at least ten)
Warbling Vireo (a dozen)
Rufous-crowned Sparrow (a pair, foraging together)
Orange-crowned Warbler (many, numerous)
Wilson's Warbler (all over the place, probably 20)
Ash-throated Flycatcher (two pair)
Black-headed Grosbeak (a couple of territories noted)
Pacific Slope Flycatcher (most likely)
Black-headed Grosbeak (two pair, returning to previously observed territories)
And, of course, many House Wren and Bewick's Wren.
Good birding, and good health to all,