EA 110 – Field Ornithology – Class VII

16 October, 2007 by Adam R. Paul

(this is a back-dated post – I’m a bit behind on posting my class notes)

Today we started in on page 178 of the National Geographic Field Guide to North American Birds, beginning with…

Great Knot (GRKN):

Red Knot (REKN):

black and orange buffy back in alternate plumage
around the size and shape of a Dowitcher, but with a shorter bill and lacking the white back stripe in flight
its orange belly extends onto its face in alternate plumage
it’s an uncommon migrant and rare winter visitor to the SF Bay Area
seen mostly along immediate coast on tidal mudflats
April is the best time to see them here in alternate plumage – they’ve been observed in the past at Coyote Point
have a relatively straight bill
basic plumage is gray with a prominent white supercilium
they wade deeper than many other shorebirds, up to their bellies
juvenile has a white terminal band and black sub-terminal band on the scapulars
they’re easy to overlook in basic and juvenile plumage, as they’re unremarkable and nondescript, similar to a Willet, but 1/2 their size
often associate with Dowitchers
forage primarily on receeding, not incoming, tides
due to its short’ish bill, it feeds near the surface rather than probing deeply as do Dowitchers
when foraging it bobs its head without raising it, unlike a Dowitcher
are in a severe decline in the Eastern US due to a crash in the horseshoe crab population. This is because REKN depend on eating horseshoe crab eggs, and horseshoe crabs are being extensively collected for scientific/medical research
have a greyish white rump in flight
have a thin white wing stripe
yellowish/greenish legs

Sanderling (SAND):

You have reached the last slide
Sanderling at Princeton-by-the-Sea

have buffy head in alternate plumage
juvenile is all-white underneath
have large-looking eyes that stand out on their face
are abundant on the SF area coast
have a white face in basic plumage
black legs
have no rear toe, just 3 front toes, unlike other Calidris
basic plumage ghostly pale above, pure white below
~same size as a Dunlin
face is lighter than a Dunlin’s, which is more grey/brown above, and has a larger bill than does SAND
Western Sandpiper (WESA)’s eyes look smaller since its face isn’t white
it’s the only “peep” typically seen on sandy beaches “chasing” the waves in flocks.
exhibit “clockwork toy” running to and fro, like a wind-up bird
breed in the Arctic tundra and winter on most of the world’s coasts
are one of the most widespread shorebirds worldwide
similar Snowy Plover (SNPL) has a much shorter bill and a broken breast band, but SAND can be confused with SNPL if it’s a bid wind-blown and the bill is not visible
in alternate plumage it can look a lot like a Red-necked Stint (RNST), so beware!
can also be mistaken for Baird’s Sandpiper (BASA)
has fairly bold wing stripes in flight

Dunlin (DUNL):

arctic breeder
is a northern hemispheric bird
is a common wintering shorebird in the SF Bay
has reddish upper parts w/a large black belly patch in alternate plumage
has a medium-length bill that droops at the end
wades in shallow water, rather than in mud like WESA
there is much geographic variation and quite a number of subspecies
American subspecies used to be called the Red-backed Sandpiper
juveniles stay on the breeding grounds through their first molt, so we in the SF area hardly ever see juvenile Dunlins (recall most other sandpiper juveniles leave the breeding grounds before their first molt, so we see them in juvenile plumage, and are followed 4-6 weeks later by adults)
Rock Sandpiper (ROSA) also has a dark spot on its chest in alternate plumage, but it’s much smaller than a Dunlin’s
in basic plumage, head is all-dark with a nceck band, and the eye doesn’t stand out
has the longest bill of any “peep”
in basic plumage, has plain upperparts and a faint light supercilium, with a contrasting demarcation between the darker upperparts and light underparts
they’ve just recently arrived for the winter in the SF Bay Area, so keep an eye out for them
can number in the 100,000s in SF Bay
have a white wing stripe, white-edged tail w/dark center, like most Calidris

Curlew Sandpiper (CUSA):

Eurasian bird, vagrant in North America
most records are in the eastern US – they’re very rare on the west coast
is a rare visitor to Alaska
plumage similar to Red Knot (REKN), but bill is simliar to Dunlin’s
there’s 1 record for SF, in Lake Merced
are larger than WESA
are long-winged, and have long primary projection
bill is curved throughout its length, rather than at the tip like a DUNL
DUNL has shorter legs than CUSA, especially the tibia (above the knees)
has an all-white rump w/no darker center, unlike most Calidris sandpipers
can be confused with Stilt Sandpipers (STSA), but CUSA has black legs vs. yellowish legs for STSA
juveniles have buffy washed appearance
have faint eye line