Shore bird help in nyc (1 Viewer)

One more from yesterday

Semipalmated Sandpiper

CARERY said:

Semipalmated Sandpiper

Click to expand...

White-rumped sandpiper. Note the streaks running the length of the flanks, dark bib and large bill and of course the white rump

Is that a completely white rump, or is the angle only showing one side of the rump/tail? I thought the apparent dark flank markings would suggest White-rumped, but happy to stand corrected.

EDIT: cross-posted with Tom. Looks like my impression was correct.

To me it looks more like the seemingly completely white rump is a matter of the perspective. I mean to see a dividing dark line but wouldn't want to insist. Are there more pic of this bird? The other features mentioned might point to White-rumped but I'm still not convinced.

white-rumped sand for the reasons tom mentioned.

CARERY said:

To me it looks more like the seemingly completely white rump is a matter of the perspective. I mean to see a dividing dark line but wouldn't want to insist. Are there more pic of this bird? The other features mentioned might point to White-rumped but I'm still not convinced.

Click to expand...

It is fair to say the white-rump is a little subjective to be clear. I'm not 100% sure how a Semipalmated rump in this exact position would look. I get the impression that we are seeing enough white on the rump to use it as a field mark, but it probably depends on how you interpret what parts of the bird you are seeing in the photo. That being said, the streaks along the flanks alone are enough for WRSA.

I'd like to stress that I really don't want to push the matter just to learn. I thought the marks at flanks of a White-rumped would be more extensive. The OP has only rather few markings. I found a photo of a SemiP with almost as much streaking at the flanks as the OP: http://s3.amazonaws.com/birdfellow-production/content/bird_photos/000/018/750/identification/SESAflight-08Jul-Sequim1a.jpg?1282435227

As for the large bill. I've read that it can vary a lot in SemiP and some populations have rather long bills... Again, just want to learn!

CARERY said:

I'd like to stress that I really don't want to push the matter just to learn. I thought the marks at flanks of a White-rumped would be more extensive. The OP has only rather few markings. I found a photo of a SemiP with almost as much streaking at the flanks as the OP: http://s3.amazonaws.com/birdfellow-production/content/bird_photos/000/018/750/identification/SESAflight-08Jul-Sequim1a.jpg?1282435227

As for the large bill. I've read that it can vary a lot in SemiP and some populations have rather long bills... Again, just want to learn!

Click to expand...

The bird in the picture you shared is a semipalmated sandpiper. Every once in awhile they approach Western in regards to chevrons showing onto the flanks. Normally I don’t think they show that extent of streaking on the flanks, but nonetheless the difference between white-rumped is that 1. The streaks do not extend as far down the flanks, compare to the OP where the streaks run neatly and thin along the axillary all the way to the trailing edge of the wing. The SemiP you shared, the streaks appear to be a continuation of the breast bib. 2. The bib of the OP bird is typical of WR and not of SemiP in that it is densely marked and forms a lateral and clear demarcation with the white belly compared to SemiP. Least sandpiper and pectoral sandpiper, to name a few, also have the clearly defined lateral border between dark bib and white belly.

With regards to bill size variation, it is true that SemiP show some noticeable variation, but not to the extent of overlapping with the OP bird. This is a difficult thing to judge for anyone, especially in the field at a distance. Usually SemiP and Western are the ones that will overlap with regards to bill size/shape. In addition to the size WR has a very subtly different bill shape than SemiP and can be seen in the OP picture. It has a more tapered tip and overall more stretched, longer appearance. It is typical for SemiP to have a thick and blunt tipped bill, but this is variable to some extent. This is why it’s hard to visualize without a lot of experience.

In the field you usually won’t have a problem with WR in flight, but sometimes the white-rump is actually difficult to tell apart from the pattern of the other peeps. In flight, size is more easily honed in on compared to on the ground, probably because the sky contrasts the bird more than a mudflat does and provides a more well defined outline of the bird, and of course you also get the longer wing span which also aids in showing the birds overall larger size.

On the ground I can usually pick out WR among the groups of SemiP and Least by scanning for the ones that look long-winged, large headed and large chested. They have some girth that stands out most of the time. Long wing tips alone are misleading because SemiP can vary their posture in ways that the wing tips cross and start to mimic WR closely

Wow Tom, thanks a lot for taking the time to write this long and informative post!

Except that the bird's rump is not white. But, that's fine, as White-rumped Sandpiper does not have a white rump -- it has white upper-tail coverts!

TLeukering said:

Except that the bird's rump is not white. But, that's fine, as White-rumped Sandpiper does not have a white rump -- it has white upper-tail coverts!

Click to expand...

Put forward a proposal to AOU to have it renamed 8-P