Date: 9/8/26 1:22 pm From: Dominik Mosur via groups.io <dominikmosur...> Subject: [EBB-Sightings] San Ramon area migrant notes and Pleasanton Kite Roost - Labor Day Weekend (9/6 and 9/7 2026)
I spent Sunday 9/6 birding around San Ramon (Contra Costa County) to see what signs of migration could be detected in the suburbs and yesterday reprised a 7/20 hiking loop of Las Trampas Regional Wilderness along Rocky Ridgewith the same goal.
Overall numbers of migrants were lower than I had anticipated/hoped for but there were still a few things that I found notable enough to share with the list. One thing I found interesting was that while my weather app indicated a 2-5 mph Northeast wind in San Ramon, Rocky Ridge (elevation ~2000') was blown out at a steady 15-20 mph with gusts so strong that I had to hold on to my scope to keep it from getting knocked over.
Vaux's Swift - a loner flew over the Las Trampas main staging area with 3 unidentified Swallows early in the morning. I was hoping the Northeast winds would bring more but that was it in ~5hrs. It was the first one I've seen this fall
Say's Phoebe - singles were on the Iron Horse Trail and at Old Ranch Park in San Ramon. Early September is when Say's start to arrive for the fall/winter season but in recent years I've noted them breeding just a few miles east of here so these may be locals
Violet-green Swallows - 3 flew over Rocky Ridge/Las Trampas ,the first ones I've seen this fall
Red-breasted Nuthatch - the region wide irruption was in full evidence with several calling from the oak/bay stands along the Las Trampas Elderberry Trail. (2) flew past me on Rocky Ridge from the Watershed lands heading down into the canyon
House Sparrow - a flock of (~20) along the Iron Horse Trail next to Montevideo Elementary were notable to me because it's the first time in dozens of efforts going back to 2021 that I have encountered this species within San Ramon City Limits. MINDBLOWING!
White-crowned Sparrow (Pugetensis) - a somewhat early migrant HY White-crown was along the Iron Horse Trail at Pine Valley Rd.
Rufous-crowned Sparrows - 4 pairs noted along the Rocky Ridge/Elderberry Trails in Las Trampas were all in spots where I seem to encounter this species on every visit. It appears that similarly to California Towhees, Rufous-crowned Sparrows maintain a territory and pair bond year round
Tricolored Blackbirds - a few of these could be heard giving their distinctive "what's wrong with that cat" vocalizations mixed in a flock of (~200) Red-winged Blackbirds on the natural turf axillary ball fields of California High School next to the Iron Horse trail. Another data point emphasizing the danger of the artificial turf conversion trend that seems to be so prevalent in these days
MacGillivray's Warbler - a hy female in coyote brush surrounded by parched grassland was an obvious migrant, as engaged in a conversation with one of the Rufous-crowned Sparrow pairs along the Elderberry Trail in Las Trampas. It was my first encounter with this species ever in Contra Costa County since I refuse to bird Mitchell Canyon or the Berkeley Hills on general principle.
I also wanted to pass on a report of an amazing spectacle taking place in Alameda County in Pleasanton in the past two weeks. Starting 8/28, fellow EBBirder Isabelle Reddy has been noting a massive White-tailed Kite roost gathering in the vicinity of Ken Mercer Sportspark and Woodthrush Park. Isabelle noted 20 kites the first evening 8/28, 78 on 9/1,133 9/3, 175 9/4, 224(!!) 9/5, 142 9/6 and 112 9/7. Per Isabelle the roost appears to have shifted as of last night but the kites keep coming each evening starting about an hour before sunset and quickly departing around first light the following morning. Isabelle will be out of town for a while but I would encourage other birders/citizen scientists to come by and continue the effort of counting these birds and tracking where the roost shifts to.
Per eBird data this is the largest roost of White-tailed Kites in the United States of AMERICA!
