White-rumped Sandpiper at Bolsa Chica ORA
- Hi Calbirders,
At about 3:45 PM, Brian Daniels and Leo Ohtsuki reported a White-rumped
Sandpiper at Bolsa Chica Ecological Reserve to the SoCal birdbox. The bird
was in the fenced-in area at the north end of the boardwalk that crosses
the estuary from the parking lot.
Jim Abernathy and I arrived just before 7 PM, and found the WRSA fairly
quickly. It was on the far side of the impoundment on a mud flat with
several Semipalmated Plovers, a Snowy Plover, a Western Sandpiper, and an
alternate plumaged female Red Phalarope. We watched, photographed, and
video taped the bird until it flew off with the other birds, just before
sunset. As the mixed flock seemed to be sticking together and may only have
gone to a nighttime roost, it is probably worth checking for the WRSA
tomorrow. If you go and the bird is in the same place as today, you will
definitely need a scope.
The WRSA is an alternate plumaged adult, and easily separated from the
smaller Western Sandpiper by its longer (Baird's Sandpiper-like) body, long
straight bill, and long legs. The crown shows some rufous, the supercillium
was pale but not clean, and the flanks were streaked. Mantle was
rufous/brown with one pair of pale braces. The primaries clearly extended
beyond the tail. The bird flicked its wings once while I was taping, and
again a bit later. I have not checked the video yet to see if the white
rump was caught on tape, but I did see it the second time. The bib, while
mostly black streaks on white, did show some buff. The area between the bib
and the wrist of the folded wing was streaked, but mostly white. These two
characteristics, along with the amount of rufous on the crown, may indicate
a first year bird undergoing the end of a late molt. Sibley says that
alternate plumage runs from April through August.
For those who don't know, Bolsa Chica is on Pacific Coast Hwy. southeast of
Warner Ave. in Huntington Beach.
Steve Sosensky, SoCal Bird Guides www.sosensky.com/guides/
<mailto:steve@...> for general use
<mailto:mobile@...> rare birds and emergencies only
Toluca Lake, CA 91602 818-508-4946 34.15645 N, 118.36715 W
SoCal FRS: use channel 11 code 22 SMS: stevesosensky@...