June 2021 – Heermann's Gull (Larus heermanni, Order Charadriiformes, Family Laridae - Gulls >).  Notable for its, distinctive red bill; Allaboutbirds.org says that this is "probably the easiest to identify gull in North America."  [Top: breeding adult; below: non-breeding adult].
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The feet are the right color but I'm not sure if this is a juvenile Heermann's Gull.  I did note this behavior several times; it is not clear if they hoping to catch a sand crab or what.