May 8, 2012 Least Sandpiper or Long-toed Stint?

Here are some observations and thoughts from excellent and expert birders regarding the correct identity of the tiny, 6" shorebird that is going about its business, totally unconcerned about the fuss. After all, IT knows exactly who it is, where it came from, and where it's going. It's a fun puzzle for us humans to try to figure out. 

For further discussion, please go to AK 

Happy Birding!
Carol Griswold
Seward Sporadic Bird Report Reporter

May 7, 11:57 pm from Steve Heinl
Separating Least Sandpiper and Long-toed Stint in alternate plumage is extremely difficult.  The call notes are very different (Least is a bright, rolling, upslurred "breeep" with a strong "ee" sound, and Long-toed is a rougher, lower trill).  The other main characteristic is that Long-toed really does have longer toes, particularly the middle toe.  The toes on this bird look normal for Least Sandpiper - they don't look long to me.  Long-toed Stints also nearly always have dull yellowish or olive at the base of the lower mandible, and this bird's bill looks like it is entirely black.  There are some other subtle plumage differences between the two (but those characters can overlap), but given the fact that the bird doesn't look long-toed and has an entirely black bill I think that the bird is a Least Sandpiper.

May 8, 8:08 am from Buzz Scher Anchorage
I agree this may not be your 'typically' plumaged Least, but that's what I believe it      is -just a slightly brighter, fresh plumaged one. I don't have a lot of experience with   Long-toed, but what I remember most (in fresh alternate) was that the bird reminded me of a small, juv Sharp-tailed Sandpiper (although I may be the only one on the     planet that thinks that); with bright orange-brown fringes to the tertials, brighter (less chocolate colored) back, slightly brighter orangish crown (which helps 'set off' the     supercillium), and particularly distinct broken streaks over a buffy-orangish wash      across the upper breast - all lacking in the Seward bird. Also, as Steve said earlier,      the middle toe is VERY long - what I recall it seemed longer than the bill - and the   base of the lower mandible is pale; again both lacking in the Seward bird. That said, did you happen to see it next to a Least (LT is longer-legged and slightly greater in mass).

May 8 at 9:30 am from Tasha DiMarzio and Seth Seward
Just a quick update:
As of now the species ID has yet to be confirmed.
Seth went back out this morning and found the bird in the exact same spot, no other birds with it; the bird was still bathing and feeding.

We are aware that the Least Sandpiper and the Long-toed Stint are strikingly similar but the one thing I did not include in the first report was the behaviors that we saw and some other identifiers that can't be picked up in photos.

The reason we thought that this bird could be different is because of its
behavior and it had a feeding style I have never seen before. It was very bent over and kind of squat-like. The movement of the bird had an awkward gait. 2 different groups of Least flew over calling and the bird had no reaction at all to them.

In Carol's photos the beak does look all black but earlier in the day when the sun was on the bird the base of the bill did seem to be two toned. Without having a book in hand right away this was one of the characteristics that was listed. Also in the photos the bird then was in the mud and the toes were spread out. When we saw it earlier when it was feeding on the other-side of the bank in the rocks, the middle and back digits were noticeably longer. It would also hunt over and balance over and balance on its tarsus while feeding.

This morning when Seth found the bird roosted he flushed the bird and when the bird called it was very different call; more sounding like a songbird, more of rolling chirp, not as sharp, or trill as the Least.
When he heard its call he's now convinced it's not a Least.

Given these behaviors we feel it's not a Least. Can any one weigh in on

May 8, 10:28 am from Aaron Lang, Homer
OK, I'll jump in. In all of Carol's photos the posture looks hunched over
and creeping. This crouching feeding style is typical for a Least
Sandpiper. Long-toed Stints have longer legs and necks than Least
Sandpipers which give them a more up-right stance when at rest and alert,
and a more "tipped over" posture while feeding. Your description of the
feeding style seems to support Least. While a single photo can be
misleading, I would expect at least one in 10 photos to show a posture more typical for Long-toed. On Carol's last photo the middle toe doesn't look long enough for a Long-toed, which on that species should be just longer than the tarsus. The best test of this is to see the bird in flight--do the toes project beyond the tail in flight?

Overall, this bird looks too dark and uniform (lacks contrast) to be a
Long-toed. I would expect a Long-toed to have more prominent supercillia
and lighter lores as well as a more prominent mantle "V". The lower
mandible appears to be black, which supports Least. Some bright Least
Sandpipers have the bright, warm tertial fringes that this bird has.

The call of a Long-toed Stint is similar to that of a Least, but it's
lower--about the same pitch as the call of a Pectoral Sandpiper.

Thanks very much for getting my brain fired up this morning with a
stimulating shorebird ID question!

May 8, 10:51 am from Aaron Bowman, Anchorage
Great ID thoughts on these two species, thanks for bringing it up.
I would agree with Aaron Lang about the posture of the long-toed vs. the least.       In Japan near my house I would regularly see long-toed stints in the
rice fields in migration and could pick them out at a good distance
form the other small species based on their upright long-necked
appearance. The long-toed when feeding almost looks like it is using
its height to look down at its prey rather than a least crouching
after it. On my first glance the facial characteristics also looked
somewhat different, and the chest markings also do not quite look
right for a long-toed. Those were my first reactions....

May 8, 12:15 pm from Sadie Ulman, Seward
Overall gestalt of this Calidris seemed off from the `normal' visitors. It was
feeding on small exposed rocky area in sheltered slough bottom (2-3 ft wide, and slough banks ~3 feet tall) bend at outgoing tide. Slough is outflow from big freshwater lake, and inland from mudflats. Bird was walking slowly over rocks and in shallow water, picking forage items off surface of rocks and in shallow water. We watched bird for almost 2 hours of constant foraging. It did not flush.
Behavior: seemed different than a least sandpiper. I have not observed stints, but this bird seemed to be foraging more slowly and w more intent (and in different habitat) than leasts I have observed on vegetated mudflats (very similar to Seward airport) during migration.
I put pictures in "Ulman" folder (on AK Birding website)- these photos were taken a bit earlier than Carol's and had slightly different lighting (i.e. paler lower mandible is shown)
-lower mandible is paler at the extreme base. This was a different field mark noticed before field guide came out.
-plumage: Seward bird appears to have more of a split supercilium, dark cheek patch, and dark forehead (darker crown continues down to bill and lores)- whereas juvenile least sandpipers typically have white forehead. Seward bird appears to to have duller wing coverts compared to scapulars
Question on mantle plumage with this bird- I'm not sure how to interpret scallop (least) vs striped (long-toed). I would think scallop means overlapping feathers in non-linear fashion. By Carol's picture #5- it seems Seward Calidris may have more linear rufous-edged feathered mantle with whitish-V? Also- when Seth went out again this morning he flushed the bird- its posture was more upright when alert walking. Overall, he likens the feeding behavior of Seward bird to red-necked stint he observed in St. Paul. Vocals he heard were not that of a least.

This is a fun, intriguing discussion for certain. The vocalization heard this
morning, observed foraging behavior, some plumage characteristics, and overall feel of the bird seem to shy away from least sandpiper. It certainly helps to have people weigh in that have seen long-toed before.
Any new thoughts?

May 17, 2012 from Martin Renner of Homer
This may be beating a dead horse, but just in case there are still people attempting CPR, here's another feature to add to the beating, that has not been mentioned so far:

Apart from (often subtle) differences in color tone, the rufous fringe of the longest tertial in Long-toed Stint is a smooth straight line. In Least Sandpiper, this fringe has a triangular-shaped bulge towards the center of the feather. This character is nicely illustrated in a landmark volume by Hayman, Marchant & Prater. I don't believe there is any overlap, although it is often difficult to see in the field. The photo in Tasha's album clearly shows this feature clearly, confirming the bird as a Least Sandpiper.

All that said, Long-toed Stint is a common migrant not that far west from us and may be one of the most frequently overlooked vagrants in South-Central.

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