Eastern Contra Costa county 12/15/18--106,000 Coots!
On 12/15, I birded at some of my preferred East county spots with Jonah Benningfield, starting early on Bethel Island. The majority of the day was spent checking this island, including Piper Slough, the Harbor road (flooded) fields, the neighborhoods on the south shore of the island, Willowest Marina and the Franks Tract Overlook. We started at Piper at dawn with hopes of high waterfowl numbers, and found expected tallies of geese but very few ducks. The real highlight of the island was the absolutely monumental number of Coots on Frank's Tract. It was impossible to get a truly accurate count, but counting by 1000s I estimated 106,000 individuals on the tract. This is far, far more than I have ever seen there, with a typical winter flock numbering in the 10-20,000 range. The flock extended across the entire tract, approximately 2.5 miles in length. It seems likely this is one of the largest coot concentrations in California at this time. I strongly encourage any experienced counter to go to this site and try to estimate coot numbers at this time. Anyway, highlights on the island included:
American Coot-106000 was an absolutely incredible count
Lesser Yellowlegs-3 in the fields was about the expected number for wintering birds
RED-BREASTED SAPSUCKER-1 was a very rare bird in the East Contra Costa county islands
PACIFIC WREN-1 at Piper Slough was my first for east county
Full eBird checklists here: https://ebird.org/view/checklist/S50712004, https://ebird.org/view/checklist/S50719211
We continued onto Orwood Road, with the primary intention of finding the NORTHERN SHRIKE originally located here by Dan Kopp and Jose Martinez. We walked around the region and Jonah eventually spotted the shrike on a pole on the north side of the road, where it perched for about a minute. It then flew east, still on the north side of the road, and landed on a wire. We lost it shortly after this point while trying to relocate it.
Full eBird checklist here: https://ebird.org/view/checklist/S50730943
Rain was picking up, but I decided to head to Bradford Island to see what was wintering on the island. We found a few interesting birds around the island:
California Quail-1 female was the first I have seen or heard reported on the island. Whether this represents a small, isolated population or moving birds from adjacent islands is unknown
Mourning Dove-130 was a nice flight at the end of the day
Yellow-headed Blackbird-164 in huge blackbird flock on South End of island.
Red-winged Blackbird-15,500 was an estimate of a massive flock on the south end of the island
Full eBird checklist can be found here: https://ebird.org/view/checklist/S50730446
Nice to see so many birds in the delta portion of Contra Costa.