Date: 7/28/20 1:02 pm From: David Bailey <davidcbaileyoregon...> Subject: [obol] RBA: Little Stint and Clatsop County Birding the past fortnight
Monday 27 July 2020 Clatsop County Oregon
After work on Saturday 25 July I birded the north shore of Trestle Bay (aka "Jetty Lagoon" on Google Maps) accessed from Parking Lot D wildlife viewing bunker trail of Fort Stevens State Park. The tide was high and starting to ebb when I got out there. The sun was low and viewing conditions were for the most part optimal when the sun was westward and at my back. I walked out east to within a couple hundred meters of the east end of the peninsula. A flock of about 100 PEEPS and SEMIPALMATED PLOVERS were working the limited mudflats there that had just been exposed by the ebb tide. The peeps were mostly WESTERN SANDPIPERS with half a dozen LEASTS. More than 80% were juveniles in fresh plumage. A juvenile BAIRD'S SANDPIPER was also in the flock. The flock allowed for close approach, likely because it was composed mostly of naive juveniles; or rather I stood still and the flock worked its way along the shore to within just a few meters of me.
Scoping the flock, I spotted two "SEMIPALMATED SANDPIPERS" (SESA) by their shorter bills. Both were juveniles (individuals that hatched this spring or summer). One was an obvious individual. I noted the short, thick bill, and the very blunt tip. This SESA had the typical large-headed appearance with relatively dull colored plumage; little reddish and buff compared to juvenile Western and Least Sandpipers. Its legs were dull gray compared to the black legs of Western Sandpiper. That is a trait many of us have noted for SESA that is not well known. The crown of the SESA was relatively pale gray and the auricular (ear patch) was weakly defined in pale gray. Being so close, I always try to discern the namesake of the Semipalmated Sandpiper--the partial webbing between the toes. Western Sandpipers are also semipalmated by the way, so there are lots of opportunities for birders in the Americas to study this partial webbing feature. I often suggest that those serious about identifying rare stints get practiced at sighting the semipalmated-toes field mark, for that webbing distinguishes all Western and Semipalmated Sandpiper from all other Calidris Sandpipers, but most especially it distinguishes the dark legged peeps that are common here from the vagrant asian breeding Red-necked and Little Stints. With some effort, I was able to see the semipalmations on this otherwise straightforward SESA, thus distinguishing it from the very similar, but very rare Red-necked Stint that I hope to someday see for myself in the field (one over-wintered at New River a few years ago; there are a few records of adults in breeding plumage from Oregon; I don't recall if we have an accepted record of a RNST in juvenile plumage yet).
The other "Semipalmated Sandpiper" in the flock I noted immediately was different. It had a somewhat thinner bill with a less blunt tip, though it was still a short bill that I judged was in the range of lengths for SESA, and certainly too short for a Western Sandpiper bill. The bird was a bit brighter at first glance, but not obviously more so (perhaps due to the low illumination as it was very near sundown) than the obvious SESA nearby. I started focusing on the toes. The peeps were all hunting very actively and the substrate was soft and wet such that when the birds put their feet down the toes were submerged in the sandy mud and so obscured. The birds were in constant moving sewing-machine motion except the machine was moving rather than the fabric. I got to distinct impressions of webless toes as this second short-billed peep lifted its foot as it walked along. I am a careful observer and have learned to resist jumping to conclusions about what I see in split seconds of observation. I wanted additional views of the toes and for longer, stiller periods of time, so that I could put all doubt out of my mind. I never got them. The wind was blowing strongly, the birds had gotten more flighty, the tide was ebbing exposing more flats for the birds to flee to, and the light was waning. I decided to head home. I figured that would be the one that got away, like so many before. I really thought that I had seen webless toes, but I didn't fully trust myself. I figured the birds would be gone the next day, continuing their journey south.
I thought about it all night and the next. At a break from work the next day I checked ebird for recent Clatsop County Checklists. Molly Sultany had logged her observations to Fort Stevens SP--Parking Area D <https://ebird.org/hotspot/L1303189> for that afternoon https://ebird.org/checklist/S71839324. Molly's checklist logged 2 SEMIPALMATED SANDPIPERS; she had photos. BINGO! From the photos I discerned these were the same two peeps I had logged as SESA the day prior. The are different looking birds, One had obvious braces and an overall slighter appearance; the other was larger and duller. I emailed Molly and several local birders of my suspicions and asked Molly if she had additional photographs of the "Semipalmated Sandpipers." Longer story shorter, she did. She sent them to me. I sent them off to two other birders to evaluate. I heard back from one whose response supported my hypothesis. Molly's photos show the bird in question with its toes spread in a few of them. The photos suggest webless toes. The photos show a darker crown and split supercilium (a weaker, but apparent eyebrow stripe that goes from the prominent white eyebrow at the forehead up over the dark-streaked crown). The primary projection (the blackish primary tips that extend past distally past the warmer plumaged tertials in the folded wing) is not long (or is it?). I think I see three primary tips visible past the tertials in one of Molly's photos, but the folded wings don't give me the impression of long wings like they do in Western Sandpiper in similar posture. The bird is more darkly marked than the SESA it was near. Overall, my impression is that this second "SESA" is actually a rather pale-plumaged LITTLE STINT. There will need to be further analysis to rule out Red-necked stint, but I think the well-marked, paired braces due to the white edges of the median coverts and the lower scapulars, short primary extension, slighter and pointier bill, and dark crown favor LITTLE STINT over Red-necked.
Jim T. Johnson and I photographed and identified what became the first state record of Little Stint for Oregon back in September 1985. That was also a hatch-year bird in juvenile plumage. I have not knowingly seen a stint since then. I still hope to find a Red-necked Stint one day, and I do not completely rule out that the bird seen last week could, upon further examination and analysis be determined to be that species. Stints are very difficult to identify, especially those in juvenile plumage. I hope that Molly will make her photos available to all for additional birders to examine on their own.
Other notable birds around the coastal plain of Clatsop lately include a WILSON'S PHALAROPE that was hunting the island in Trestle Bay the evening and high-ish tide of 24 July. Multiple reports from lower tide periods at Trestle Bay include lots of Marbled Godwits and WHIMBRELS, and a few BLACK-BELLIED PLOVERS. Clatsop Beaches are hosting Whimbrels and a peeps as well, but have underwhelmed. The Necanicum Estuary has also been less exciting, but a handful of peeps and SEMIPALMATED PLOVERS, a SHORT-BILLED DOWITCHER, a LESSER YELLOWLEGS, and a few WHIMBREL have been around. A pair of WANDERING TATTLERS have visited the cove with the BLACK TURNSTONE flock. Others have reported RUDDY TURNSTONE, but beware the red legs of Black Turnstones can trip up an identification. SOOTY SHEARWATERS are streaming offshore about half the distance to the horizon when viewed from sea level. Lots of Brown Pelicans are feeding the surf. Heermann's Gull numbers are increasing each day as expected. Boobies of multiple species are being seen off the Farallon Islands nearby off mainland California, so one can hope for more Oregon sightings!