Pectoral Sandpiper at IRRI - A first record for The Philippines

On 10th October 2013 while birding in the ricefields at IRRI I came across an interesting sandpiper. Medium sized, it at first glance appeared to be a juvenile Sharp-tailed Sandpiper. I took a number of record shots for my blog, then continued on my birding day (see here). On 12^th December I received a comment on my blog from a visitor (Tom Sacher of the German Rarities Committee (DAK)) that the bird may not be a Sharp-tailed Sandpiper, but in fact looked like it was a juvenile Pectoral Sandpiper, previously unrecorded in The Philippines. I think he was right. With hindsight I wonder at my initial misidentification. A clear example of Inattentional Blindness.

Juvenile Pectoral Sandpiper. 10th Oct 2013.

Pectoral Sandpiper (PSP) have an unmarked belly which is sharply demarcated from a streaked breast. Sharp-tailed Sandpiper (STSP) have some dark markings along the flanks. The 10/10/13 bird shows clean flanks, and a sharply demarcated division between a white belly and streaked breast. It is impossible in this picture to see the full extent of the breast however.

This STSP from 29/08/11 shows the dark feathers on the flanks (in this case chevrons, indicating an adult coming out of breeding plumage), as well as the less distinct division between streaked breast and cleaner belly.

Without a clear view of the demarcation between breast and belly other features must be relied upon. A close examination of the head I think provides enough evidence for a confident identification.

PSP show a less distinct eye ring than STSP. They also have no rufous in the crown, which STSP usually does. STSP also have a darker and better defined band on the ear coverts. The base of the bill of PSP is yellowish brown or greenish brown, while STSP has a pinkish base to the bill. STSP has a whiter and more distinct supercilium. STSP also averages shorter bill and shorter neck than PSP, and with a slightly flatter crown.

The bird seen on 10/10/13 shows most of the features that correlate with PSP. The base of the bill is brownish, not pink. It does not have a prominent eye-ring or any rufous in the crown. There is no dark band on the ear coverts, and the supercilium, while fairly distinct, is not whitish. It also has a noticeably long-necked appearance

The STSP from 2011 showing a pale eye-ring, darker ear coverts, rufous crown, distinct whitish supercilium and paler (pinkish?) base to the bill.

It has a clearly split supercilium, a feature of PSP but not of STSP.

The clear ‘braces’ formed by the whitish fringes to the  edge of the mantle and upper scapulars are typical of juvenile PSP, though I have seen photographs of STSP with similar, though less distinct patterning.

One further feature separating PSP and STSP is primary projection. PSP has a long primary projection, on STSP it is usually shorter. The top picture here is the PSP from 10 Oct, and the lower picture is the STSP from 2011. Clearly the top bird has a noticeably longer primary projection.