EA 110 – Field Ornithology – Class 1

Wednesday was the first class in the fall semester of Field Ornithology at CCSF/Marina Middle School.  Unlike the class I took in the first half of this year, which was a complete survey of the birds of North America, EA110/115 and EA120/125 are years-long classes, going through the birds of North American in quite some detail (the only difference between 110 & 120 is the day of the week, and where they are in the book).  According to Joe Morlan, who teaches the class, it takes about 6 years (!!) to get through the entire book, as each 2-hour class typically covers only one page.  We’ll see if I make it that long, but I certainly look forward to covering shorebirds & gulls in-depth for now!

I will endeavor to keep up on the notes as the class goes on, but I only batted about .700 last semester, so we shall see 🙂  My notes for this class follow.

We started with a discussion of students’ observations over the summer break, including a Buff-breasted Sandpiper seen this week at Heron’s Head park in SF.

• Many shorebird populations, including the Buff-breasted Sandpiper, were decimated by the practice of “Market Hunting” in the early 20th century
• Although some birds have recovered (Marbled Godwit, Willet, Long-billed Curlew especially), many have not (Eskimo Curlew (extinct?), Buff-breasted Sandpiper)
• The ones that haven’t recovered are long-distance migrants, and are still hunted in South America
• The Market Hunting season was in spring and fall.  Spring hunting was especially detrimental to populations, since the birds shot were en-route to their breeding grounds.  This is why all (nearly all?) hunting seasons in the US are in the fall nowadays.

Joe went on a several-week trip to South Africa over the summer and saw nearly 400 bird species, nearly all of which were life bird for him(!!)
We started on p162 of the 5th ed. of the National Geographic Field Guide to North American Birds, with Willets and Lesser & Greater Yellowlegs.

Scolopacidae:

• have a long, thin bill for probing in mud
• bill is soft and fleshy
• the tip of their bills are prehensile – they can open just the tip through tendon action.
• taste organs on the tip of the bill alert them to the presence of food, then they open the tip to grab the prey, pull it out, and gulp it down.
• Shorebirds are aware of the tides, and flock to an outgoing tide, as their prey are underwater then, and haven’t yet burrowed deep into the mud; so the best time to see shorebirds is during an ebbing tide
• Since they can’t see their food anyways (it’s under-water or under-mud), they feed day and night, sleeping during high tides.

Tringa genus:

• “high-step” and bob when they forage

Willet:

• used to be in its own genus, Catoptrophorus, but is now in Tringa along with Yellowlegs and some less-common birds
• are “sempalmated” (have partially-webbed feet)
• are a common winter sight in the SF bay area
• breed inland in freshwater marshes
• on breeding grounds, male’s call is the origin of the bird’s name “Pill will willet”
• we see them in the summer here too, mostly 1st summer birds, too young to breed
• some adults stay into early summer, waiting for the tundra to melt so they can nest
• adults also migrate south from the arctic early, in July/August, abandoning their young, who follow in August/September
• 2 subspecies, ssp. semipalmata summers in the east coast and winters outside of North America.  ssp. inornata is the one we have here in the western US
• grey bill, grey legs, barred brown in alternate plumage, plain grey in basic plumage
• wing stripe, on both top and bottom of wing, is diagnostic when wing is unfolded
• juveniles migrate in their juvenal plumage, molting at the wintering grounds
• juv Willets (and presumably other birds) do not molt their flight feathers (primaries, secondaries, tail feathers) during their first winter molt, so it can’t really be called a pre-basic molt, since the resulting plumage is a mix of juvenal flight feathers and basic body feathers.  This plumage has been named the “formative” plumage.”   The plumage sequence for such birds goes: juvenal -> formative -> basic -> alternate
• The sometimes-visible apparent black “rump” on winter willets is actually the black 1st primary feather, mostly covered by the tertials.
• Willets have little primary projection (the amount of primary feather that juts out from under the tertials when the wing is folded).
• can be found on any coastal shoreline, rarely seen inland other than on their breeding grounds; they fly mostly non-stop to the coasts

Yellowlegs:

•  GRYE (Greater Yellowlegs) and LEYE (Lesser Yellowlegs) are quite similar
• LEYE is a rare migrant and a very rare winter visitor in the SF bay area
• GRYE is a common visitor
• Both YE are found in brackish water, sewer ponds, flooded fields, and tidal estuaries.  They like salt water that has some fresh water flow
• Both YE have yellow legs, but these can be obscured by mud/muck, and some have orage’ish legs
• most LEYE seen here are juveniles, while GRYE tend to be adults
• LEYE travel further, and are not likely to winter here.  They also molt at their wintering grounds, so a YE undergoing its pre-basic molt is most likely a GRYE
• Although size is a dangerous and unreliable field mark, since both YE are sometimes seen with Dowitchers, a LEYE will appear clearly smaller than an adjacent Dowitcher, while a GRYE will appear clearly larger (doesn’t matter if the Dowitcher is Long- or Short-billed, as they’re about the same size)
• LEYE has a straight, all-black, and needle-like bill, which is ~equal to the diameter of its head
• GRYE bill has a paler base, appears heavier, and often looks to curve up slightly, and is greater than the diameter of its head
• GRYE call is loud and descending,  LEYE call is softer and even.
• GRYE have barring on their flanks in alternate plumage, while LEYE have clean flanks
• juvenile & wintering YE look very similar
• generally a combination of traits is necessary to identify a GRYE vs. LEYE, unless the bill shape is obvious, which it often isn’t
• Females of both YE species have longer bills than the males

After this, we played “name the bird,” where Joe would put up a slide of one of the above 3 birds, then call on someone to list the relevant field marks and identify it.  This was a fun game, which we’ll apparently do in every class.

In case you’re wondering, I correctly identified my Willet, which, since it was in flight, wasn’t too much of a challenge!

Advertisements