ML476906601
Contributor
Date
Location
- Age and sex
- Adult, Unknown sex - 1
Media notes
A worn, adult Stilt Sandpiper beginning its prebasic molt found earlier in the day by Tom Wurster, here photographed with a Greater Yellowlegs by Curtis A. Marantz on 16 August 2022 at the San Joaquin Marsh and Wildlife Sanctuary, Irvine, Orange County, California.
Observation details
I spotted the continuing sandpiper standing in the middle of Pond C almost immediately upon my arrival, and this bird remained in view at various locations around this pond throughout the time that I spent here, though it did move between the center of the pond and both the northwestern and southeastern shorelines. Although this bird was generally closer to the trail when along the southeastern shoreline, the light was much better than looking from the west. I saw this bird fly only once, but I lost it almost immediately when it took flight, so I saw essentially nothing on the flying bird. I also saw this bird preening extensively, feeding at times, sleeping with its head tucked while standing in the middle of the pond or along the shoreline, and I once saw it raise its wings, but I never heard it vocalize. I studied this bird carefully and I took quite a few photos before leaving it foraging along the northwestern shore of the pond. Overall, I thought this bird looked much like a slim, grayish dowitcher, and its foraging behavior was quite similar, in that it stood belly-deep in the water and probed extensively rather picking at the surface like a yellowlegs. This was a relatively small sandpiper that was nevertheless larger than the peep that were often foraging in close proximity along the shoreline, and even a little larger than a nearby Wilson’s Phalarope, yet it was quite a bit smaller than a Greater Yellowlegs. Oddly, I never saw this bird in direct comparison with the two dowitchers that were also at this pond. I thought the bill was about 125% as long as the head was wide, and I noted that it tapered from a base of medium depth for a sandpiper to a finely pointed tip along a culmen that appeared to be straight for at least most of its length, and in fact, I did not really notice much of a droop distally. The forehead was sloping, and the crown was weakly rounded, both on a head that appeared small for the bird’s size. The neck was of medium length for a sandpiper, and slimmer than those of the smaller species, but probably not too different in mass from that of a yellowlegs. I thought the body was plump and both somewhat full-chested and pot-bellied, and I noted that this bird often stood belly-deep in the water. The wings appeared to be of unremarkable length for a sandpiper, in that they reached right to the tip of the tail. I noted a short projection of the primaries beyond the longest tertial, but I failed both to count the exposed primary tips or compare the primary projection with that of the exposed secondaries (though a rough guess would have been about a fifth the length of the exposed secondaries). Given that I never clearly saw a tail that was typically obscured by the closed wings, I could only estimate its length to be roughly one-half to two-thirds the length body without the head and neck. I also cannot ever recall this bird standing on dry land, and in general, I saw little more than the uppermost part of the tibiotarsus extending above the waterline. This was a relatively well-marked bird even though it was a molting adult that had already replaced most of its mantle and scapular feathers, and at least some of those on the head. The crown appeared to be a medium-gray in color with at most subtle streaking; however, I did think the gray of the crown may have blended into a darker and more brownish color on the forehead. Demarcating the lower edge of the darker and more grayish cap, was a pale gray to dull whitish supercilium that was relatively conspicuous as it extended from the base of the upper mandible back through the supraloral region, over the eye, and back along the upper edge of the auriculars to their rear terminus and slightly beyond, but the supercilia did not continue back to the nape. I generally thought the nape and the back and sides of the neck were a slightly paler shade of gray than the crown, but the difference was subtle. The same gray that characterized the neck extended forward though the auriculars to the eye. I noted in the field no obvious rufous or chestnut on the auriculars, which appeared to be uniformly gray to me; however, my photos show at least some color on the bird’s cheeks. I also saw what appeared to be some fine streaking on the auriculars and the side of the neck. Before the eye, the loral stripe was narrow, but relatively well-defined, and darker than the auriculars. At times, I also thought the loral stripe may have had a brownish cast. The lower part of the face and throat were whitish, and if I remember correctly, unmarked up to the loral stripe and the lower edge of the auriculars. I cannot now recall noting any gray below the eye, but my photos do show at least some. The underparts were dull whitish, but with extensive dusky mottling that was conspicuous and relatively well-defined on the sides of the neck and breast, but with the center of the breast more weakly marked. I also have some recollection that the mottling on the sides of the breast was bolder on one side than the other, but I cannot now recall which side was more boldly marked. The belly and flanks were coarsely barred with medium to dark gray, and this same barring continued across the undertail coverts, albeit somewhat more finely. I thought the center of the lower belly was either unmarked or only weakly marked. I did not see any extension of the tail beyond the undertail coverts. Returning to the upperparts, the back and sides of the neck were a light to medium gray and they seemed to have a subtly streaked pattern internally. The mantle feathers were mostly if not entirely those of basic plumage, and thus seemingly a rather plain, medium-gray. The larger scapulars were similarly colored, but between the mantle and the main bulk of the scapulars was a narrow band of what were likely upper scapulars that had sooty to blackish markings, so the gray panels on the mantle and scapulars were narrowly separated. The median coverts were mostly obscured, but I thought they contrasted dark centers with irregular markings of whitish or maybe buff to create a complex pattern. As I recall, it was on the right side that the greater coverts had sooty to blackish centers that contrasted with a narrow yet irregularly shaped fringe, and seemingly whitish crescents distally along both the inner and outer edges. The pattern produced was one of coarse marbling, a dark overall appearance, and in places with warmer markings in addition to the generally whitish fringes. On the left bird’s left side, however, the larger greater-coverts appeared more uniformly dark brown and with a less striking pattern, and I thought the feathers along the lower part of the closed wing were a plain, light brown. The tertials appeared had sooty brown centers that contrasted with narrow fringes that were well-defined and seemingly either a deep buff or a light brown in color, though some may have had warmer tones. What little I could see of the upperside of the tail extending along the outer edge of the closed wing appeared to alternate narrow white-and-black barring, with the dark and light bars of comparable width to produce a pattern that was not unlike that of a dowitcher. My brief views of the raised wing suggested that the underwings were mostly whitish and without obvious markings. The bill appeared to be entirely dark, but I could have missed a paler base to the lower mandible. I was confident that the eyes were dark, but their precise color eluded me. What I recall seeing as that the uppermost portions of the legs appeared to be a dull, yellowish-olive in color, and my photos show the lower legs to be similarly colored, though the feet may have ben a bit darker.
Additional species
Technical information
- Model
- Canon EOS 7D Mark II
- Lens
- EF100-400mm f/4.5-5.6L IS II USM
- ISO
- 160
- Focal length
- 400 mm
- Flash
- Flash did not fire
- f-stop
- f/6.3
- Shutter speed
- 1/1250 sec
- Dimensions
- 2576 pixels x 1644 pixels
- Original file size
- 3.62 MB