Date: 7/4/25 10:00 pm From: Carter Gasiorowski via groups.io <carter.gasiorowski...> Subject: [southbaybirds] Alviso Today
Today, 7-4-25, my dad and I arrived outside the gates of Alviso Marina County Park around 7:30 am. After packing the scope onto our bikes and setting off, we were pleasantly surprised by the condition of the levees. The deep ruts from past winters have been smoothed out, making for an easy ride.
We rode straight to the north end of A9 (pond map attached) to avoid heat waves that interfere with scoping the shallow islands at the center of the pond. Once we set up the scope, we were excited to see a large number of returning shorebirds, mostly DOWITCHERS and AMERICAN AVOCETS. While scanning the flocks, I saw an odd looking log sticking out of the pond bottom. I zoomed in with the scope, and thought I was seeing the outline of feathers, but wasn't sure. Then, slowly, the bird turned its heart-shaped face towards me- it was a BARN OWL! We rode closer for a better look, and unfortunately, the bird was soaking wet and looked quite ill. The bird didn't move again for the next hour, so I fear nature may have been taking its course.
Nearby, several groups of WILSON'S PHALAROPES were sporting their gorgeous breeding plumage while spinning vigorously. Scanning the drier center of the pond revealed a few SNOWY PLOVERS doing their distinctive run-and-stop foraging pattern. These plovers were over 1/4 mile away and barely visible even at 72x magnification, so I'd recommend instead searching on A12 or A13 if you wish to see them (we didn't have time to check these ponds today). Turning towards the high-tension lines north of A9, an adult PEREGRINE FALCON flew powerfully through a dense flock of CLIFF SWALLOWS.
Just as we were packing up our bike to head back, I heard a sharp, squeaky, two-part call overhead. I looked up and saw a tern- it was a LEAST TERN! Though Least Terns are an annual post-breeding visitor to Alviso, I believe this the first sighting of the year for the county.
On our way back, we stopped to observe a large group of cormorants foraging in A10. One cormorant was vocalizing quite loudly, which isn't something I've observed before in the county. All individuals were DOUBLE-CRESTED CORMORANTS, but this may be an area worth keeping an eye on, especially with recent records of Neotropic Cormorant in Monterey and San Luis Obispo counties. We also observed at least 136 Double-crested Cormorants roosting on the degraded A14/A11 levee.
For non-bird sightings, we saw a roughly 4-foot long Leopard Shark and a Bat Ray with an almost 3-foot wingspan in A11.
In terms of closures, the construction around the east side of A12, A13 and A15 is ongoing and planned to be completed this summer. The west levee of A13 and the north levee of A12 are also closed due to Snowy Plovers breeding there. I believe it is still possible to view A15 and the north end of A13 by riding the long way (5.5 miles) around A9, but we didn't make it that far to verify.
To wrap things up, today was a beautiful, cool day that's getting me excited for the coming fall migration! My full species list for A9 is below:
Do not disclose information that identifies the location of nesting birds of any species, to minimize stress on the nesting birds and the risk of vandalism or abuse.
