Date: 4/14/25 11:00 pm From: Josiah Clark via groups.io <josiah.clark621...> Subject: [northbaybirds] Marin Big Day by bicycle report April 11
On Friday April 11, 2025 Cedric Duhalde, Jonah, Benningfield, Eric Heisy
and Josiah Clark ran a big day by bicycle in Marin. We rode about 75 miles,
climbed 5000 feet of elevation and observed 156 species (with some dirty
birds) at last count.
Highlights included the continuing tufted duck, least bittern, snow and
white-fronted goose, burrowing owl, snowy plovers, 4 species of rail, 8
species of sparrow, both orioles, BG gnatcatcher, black-throated gray
warbler and 15+purple martins.
As for the state of the migration in my experience: the numbers of Wilson’s
warblers, warbling vireos, and Pacific-slope flycatchers were notably low
even for this early date. Hopefully more will come in along with the
species we missed.
High numbers and diversity of ducks still remain, and the shorebird
migration, especially at Hamilton Field was impressive.
Large numbers of crowned sparrows remain on the Bayshore but Fox, RC
kinglet, Say’s Phoebe,varied thrushes were already not to be found.
It seemed that there were lots of hawks and swallows moving but thermals
and high winds had them out of view and quickly on the move with the first
thermals around 11 AM.
In the beginning:
We pedaled swiftly and quietly through the pre-dawn hours at the Rush Creek
preserve, a full moon and starry sky reflecting off the water as we left
the parked truck and freeway noise behind.
Where the valley Oaks meet the pickleweed is where we spent a very
beautiful and productive dawn chorus. After scoring the tufted duck among
throngs of waterfowl we booked south through Pacheco Pond, Hamilton Field
and Las gallinas. This portion was gorgeous and simply nuts.
From there we booked up Lucas Valley Road, up and over Loma Alta, through
Fairfax up to Carson Ridge, Alpine Lake and up Ridgecrest before a fast
decent into Sausalito at sunset with not enough time to fully take
advantage of the bay or ocean.
The remarkable abundance and diversity of the first part of the route
combined with excellent ears and previously scouted birds had us leaving
las gallinas with 132 species but at 130pm, much later than I had hoped.
In the end, the huge elevation gains we took on and many miles of trail
did not pay off where they have in recent years. Horned lark, Meadowlark
and Gnatcatcher usually require a trip to Loma Alta to see them in April.
Lazuli Buntings were not in yet and Rufus-crowned sparrows are increasingly
easy to miss there, and we did.
Strong gusting winds, a fast pace and the early date did not help, but I
was still surprised that with such remarkable young years in the group we
still missed migrant ash- throated-flycatcher, black-headed Grosbeak,
Western Kingbird and hermit warbler for the day.
We could not find a single golden-crowned Kinglet or red-breasted nuthatch,
which have always been expected, easy to detect year-round residents on the
conifer dominated ridge tops. In contrast Pileated woodpeckers are hard to
pin down, but two called for us. We were not so lucky with the Red
Crossbill or lingering varied thrushes I’ve had in the past.
With more hills lasting longer than I remembered, and a crew of
young companions who either did not look at the map and/or “thought you
must have been joking”, I could read the looks of annoyment in their faces.
. Even when the Ridgecrest appeared to go on forever and there were no
“new” birds to be had, we could not help but be overtaken by the
grandeur of the scenery.
By the time we reached the rock Springs parking lot the sun, blood sugar
and patience were getting low. It was all downhill from there, or flat.
(Really this time it was.) We were soon scanning the bay, picking up much
needed, but not super exciting species, including spotted sandpiper, Brants
cormorant and finally a brown pelican, flying in the lights beneath the
Golden Gate Bridge.
A much more sane, less strenuous and boring final chapter to this Big
Day probably would’ve gotten us more species in the end. Looking forward to
the seeing the various permutations of the route these young bucks come up
with in the years ahead.
I suspect they’ll break the biking big day county record of 163 species, a
record set in late April with Brian Turner about a decade ago.
Josiah Clark | Habitat Potential | Consulting Ecologist | 415.317.3978
License #1043929
habitatpotential.net
www.youtube.com/josiahmtclark
