Ohlone Wilderness Trail - Spring Migration!

Alexander Henry

Yesterday at 6 AM Phil Georgakakos, Derek Heins, Teale Fristoe and I met at the parking lot near the bridge at the southeast end of Del Valle Reservoir. From there, we hiked the Ohlone Regional Wilderness Trail up towards Murietta Falls. Although, we got so sidetracked by birding in the morning that we never quite made it to the falls, but nonetheless it was a long, tiring hike with lots of elevation gain.

As we went up and down ridgelines, we passed through a series of habitats, including dense oak-buckeye forest in the lower, lusher areas; black sage and chamise chaparral; more open oak and oak-pine woodlands; and finally open oak savannah and grasslands at the top.

It was an incredible day for migrants, by Alameda county standards at least (keep in mind a lot of the spring migrants are tougher here, since Mitchell Canyon is in Contra Costa!).

Things started off well with a Vaux’s Swift, Ash-throated Flycatchers, and a Black-throated Gray Warbler near the parking lot, then a couple Hammond’s Flycatchers in the denser oak-buckeye forest. The action really heated up when we got to the black sage and chamise patch, which is only a mile or two up the trail from Del Valle. There were 2 displaying male Calliope Hummingbirds, as well as two females, a male Rufous Hummingbird, and a MacGillivrays Warbler in the understory in a nearby gully.

As we continued farther up, we started to run into mixed flocks, and eventually would see a Nashville Warbler, a flock of 3 Hermit Warblers plus one separate individual, a Townsend’s, a few more Black-throated Grays, several Orange-crowned and Wilson’s, and many Yellow-rumped. There were also a few Warbling Vireos, a Cassin’s Vireo, a few Blue-gray Gnatcatchers, and another highlight was a lone, breeding-plumage Chipping Sparrow!

Finally when we got to the plateau with oak savannah at the top, we were treated to some beautiful Yellow-billed Magpies, a distant Phainopepla, a Rattlesnake, and great views while we ate lunch and took a well-earned break.

On the way back down, additions included a Rock Wren in a rocky field, and a soaring Bald Eagle. To our chagrin, all the Calliope Hummingbirds had disappeared by the afternoon! So definitely worth checking that chaparral patch in the morning.

Overall it was a really fun and exciting but tiring day of birding. Ohlone is a underexplored area, lots of hikers go through there but very few birders! Up until recently there was no eBird hotspot for the entire area! Unfortunately not very accessible unless you are up for the hike.

Checklist: https://ebird.org/checklist/S86300569