ML646401084

觀察細節

*rare and early for the species in SoCal but the June date is expected given this bird is an adult. *Brian Daniels photographed a SESA in alternate on the backside mid morning. While this could be the same bird I observed with others earlier in the morning, the plumage feels different to me, although the photos of mine are poor. My photos show an obvious white patch on the front of the right wing in most photos, while Brian's doesn't. The overall facial pattern and exact back pattern looks different as well but I'm not certain. Either way certainly interesting to have one, possibly two SESA in OC in June after never having a previous county record in June. Shirley Reynolds somehow first spotted this bird on the mudflats just north of the point overlook. Thanks Shirley and to the others who were helping keep track of it. The bird foraged here (33.6990962, -118.0444328) for about 10 minutes, where several of us got good scope views and relatively mediocre photos before it vanished and I don’t believe was seen again this day. This bird instantly stood out from the nearby western sandpiper in full alternate as being substantially duller with a totally different feel to it, and a shorter, straighter bill. Closer inspection over the next 10 minutes created some confusion, with some suggesting a Least Sandpiper with Muddy legs and some saying(including myself), that it may just be a western. I resorted to taking lots of photos and studying the field marks without thinking of ID. Through a combination of both of these strategies, the bird clearly isn’t a Least Sandpiper as the legs are obviously black (vs muddy green), the bird is way too gray overall, has a different build to it, and a totally diffferent plumage pattern. While I am incredibly unfamiliar with old world options, I do not think this bird is possibly a stint. This leaves western sandpiper. This bird is, unlike most SESA in California, an adult in either full alternate or just beginning its molt into basic plumage. This bird’s bill is on the long end for SESA in California, but it’s definetely within range. The bill is shorter than the majority of western sandpipers, and is quite straight without an obvious droop to the tip. The base of the bill appeared quite thick, and while this is viewed as a useful field mark I really didn’t see much difference between this area of western and semis online. This bird’s facial pattern is rather pale and white for SESA, but given that the bird is either in worn alternate or molting, combined with variation in general, I don’t view this as an issue for SESA. The bird’s breast is thinly and finely streaked (compared to less streakung and more “arrow shaped” marks of a western). Additionally, regardless of the shape of the marking, this bird’s ends cleanly and evenly about a little less than 1/2 down the bird’s breast/front, and the stomach and into the vent is clean white, whereas a western will still have streaking/marking. This bird is overall much duller than a western, which should have lots of rufous on the scapulars, head, and coverts in this plumage, and this bird has absolutely zero real rufous anywhere. While the bird has what appears to be some pale rufous throughout the back, wings and head, Kauffman’s Advanced Birding Field Guide says that “some semis are more warmly colored than others and may look pale rufous around the upperparts, face, and the sides of the crown. However, such bird’s are likely to have an overall brown cast”. This to my eyes fits this bird perfectly. The bird’s structure is more compact and less elongated looking than a western, with a rounded head shape. While definetely not concrete, the bird was gently pecking at the mud, compared to the deep probing behavior of a western. A poor video of this behavior is linked below. To my eyes the only possible issues with SESA for this bird are the slightly long and thin bill for the species, but it is still shorter and straighter than a western should be. Secondly, the bird has rufous tones, but this apparently is normal variation among SESAs. I’m willing to downgrade to a / if reviewers feel strongly this may be a western, but I’m quite confident in calling this a SESA. Many photos on my list and hopefully others.