[obol] shorebird ID class results

[Greg Gillson]

A dozen fledging shorebird watchers showed up in the heat of the day  
on Monday afternoon at Fernhill Wetlands to learn more about  
identifying shorebirds.

Fernhill Lake and Cattail Marsh were at full pool, and Eagle Perch  
Pond was dry, so shorebirding started out slow. But we found some  
shorebirds in the mitigation ponds out back that flew over to us as we  
patiently waited.

We wanted to concentrate on looking at the feathers of the wing  
coverts, which easily determine age. There are several feather tracts,  
but we kept it simple by only concentrating on two: the scapulars and  
tertials. The scapulars are the feathers at the shoulder, separating  
the wing from the back. The tertials are the innermost 3 or 4 feathers  
on the secondaries. These are extra long in shorebirds and usually  
cover the rump, tail, and primaries when the wing is folded and the  
birds are feeding on the mudflats.

The wing covert feathers on juveniles are bold and bright. The  
interior of the feathers of juveniles are usually black with bright,  
wide, margins of red, orange, yellow, and white. Each feather on the  
wing coverts thus stands out individually with a colorful outline.  
Adult winter plumage, on the other hand, is rather dull and subdued.  
We had a couple adult winter Least Sandpipers next to a bright  
immature. The feathers of the adults were brown centered with a narrow  
black shaft streak, and tannish-gray edges without much contrast.

Making the point, a Green Heron flew by. The wing feathers were  
blackish and in good condition with neat rows of white dots on the  
tips of all the wing covert feathers. What do you know--juvenile  
plumaged wing feathers in Green Herons mirrors that in shorebirds!

That pattern was repeated on a juvenile Greater Yellowlegs--neat white  
rows of dots, and also white notches on the sides of the tertials. The  
knobbier knees and bill 1.5 times the length of the head and slightly  
upturned helped with the species ID. Another Greater Yellowlegs,  
though, showed splotchy dots over the chest--an adult. Looking at the  
wing coverts we saw mostly gray with black shaft streaks, but very  
messy and disheveled. Interspersed randomly in the wing coverts were  
some all black feathers--nothing like the neat juvenile wing coverts.  
Clear across the pond, though, was a yellowlegs with neat rows of  
spots on the wing coverts. The buffy breast and more golden overall  
coloration helped identify it, even at a distance, as a juvenile. The  
bill only the length of the head, and the slighter size, identified it  
as a Lesser Yellowlegs.

Nearby was a small Semipalmated Plover. For additional practice, we  
could just make out very narrow white tips to some of the wing covert  
and tertial feathers on this plover--yes, a juvenile. Later, when it  
flew closer, some could make out an even narrower black subterminal  
mark just before the white tips. While we don't often have to look at  
the age of plovers, it is good practice and may help if we ever  
encounter a small, single-banded plover that we don't think is  
Semipalmated.

We had a dozen juvenile Western Sandpipers. The single scapular row  
was black and chestnut, contrasting with the overall pale plumage of  
the rest of the bird. Some were brighter than others, as is usual, And  
we looked at shape and behavior (often wading in nearly to their  
bellies probing in the water, while the Least Sandpipers usually  
stayed up on the dry shore or only got their feet wet and picked and  
jabbed for food).

By determining whether a bird was in adult breeding plumage, adult  
winter plumage, or juvenile plumage, we reduced the number of  
shorebird illustrations in the field guides we needed to consider to  
ONE-THIRD of the number if we didn't consider the age. We tripled our  
effectiveness of shorebird ID in just two hours!

Finally, we were ready to put our new information to the test. Someone  
spotted two of those dreaded Dowitcher (sp.) out on an island. OK,  
adult or juvenile? All agreed that each of the wing covert feathers  
were boldly outlined in bright colors. One bird had a patch of  
evenly-colored feathers on the lower wing coverts, but the scapulars  
and tertials were all bright and fresh. We agreed; these birds were  
juveniles. Now, are the tertials dark gray with a narrow cream margin  
all the way around (Long-billed) or were they blacker with cinnamon  
notches and internal swirls (Short-billed)? Everyone agreed (on a  
dowitcher?!!!); bright cinnamon edges and internal markings. Two  
juvenile Short-billed Dowitchers. They never made a peep (or a tu-tu).  
And they didn't have to!

We spent a little over 2 hours, had fun, and learned a lot. Now to go  
out again soon and keep practicing!

Monika Weiland's report to BirdNotes included these shorebirds:
1 Semipalmated Plover (Charadrius semipalmatus)
12 Killdeer (Charadrius vociferus)
4 Greater Yellowlegs (Tringa melanoleuca)
1 Lesser Yellowlegs (Tringa flavipes)
3 Spotted Sandpiper (Actitis macularia)
12 Western Sandpiper (Calidris mauri)
5 Least Sandpiper (Calidris minutilla)
2 Short-billed Dowitcher (Limnodromus griseus)

Greg Gillson
Hillsboro, Oregon
greg at thebirdguide.com
http://thebirdguide.com