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Semipalmated Sandpiper (Photo credit: Wikipedia)
The small Calidris Sandpipers of North America, peeps what many call them, can be some of the more difficult shorebirds to identify. This is because they are small and frequently are only seen from a distance so details can be hard to pick out. Also, these birds in all three plumages can look similar.
In this article I will discuss how to separate Least, Semipalmated, and Western Sandpipers. Hopefully by the end of this article you will have a better understanding on how to identify the small peeps.
Juveniles
The first plumage that I will discuss is the juvenile plumage of these birds.
When identifying juvenile Leasts from Semipalmateds and Westerns, Leasts will overall be a much brighter bird with rufous extending all over its wings, back, and breast and onto its head. There also will be a very noticeable white V that is on its back which extends from the end of the neck to the tertials of the bird.
Next, when separating Semipalmateds and Westerns in the juvenile plumage, Semipalmateds will be a much duller bird. The face of the bird will be darker and the breast will have a dirtier look compared to a Western. On a juvenile Western it will have a lighter face and breast, and it will have some rufous on the scapulars, which Semipalmateds don’t have.
Adults (Nonbreeding plumage)
Separating Least, Semipalmated, and Western Sandpipers in nonbreeding plumage can be difficult, but not impossible.
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Least Sandpipers (Photo credit: mizmak)
The easiest to identify is Least. The best way to separate this guy from the rest is by the overall brown appearance on this bird.
- On a Least its wings, back, neck, and breast will be mostly brown.
- The brown on the breast will extend up to the very beginning of the throat.
- Leasts always have yellow legs, which the other two don’t have; however, I caution you with this field ID because when Leasts have mud on their legs you cannot see the yellow, so always use this field mark with caution.
While identifying Leasts is easy, separating Semipalmated and Western Sandpipers in nonbreeding plumage is tough. The good news is that when you see a sandy colored peep in winter there’s a good chance that it’s a Western because Semipalmateds almost never winter in North America.
Apart from that to separate Semipalmateds and Westerns there are a couple things to look for.
- On a Semipalmated there will be a hardly if not any streaking on its flank, while a Western would have a lot of streaking on its flanks.
- The breast of a Western is going to be lighter than on a Semipalmated, which would be darker.
- The face on a Western can be whiter, but this is not always the case.
Adults (Breeding Plumage)
Now let’s discuss the adult plumage of these birds. This is the easiest plumage when it comes to separating these birds.
On a Least the bird will have a lot of rufous on it and it will still have a dirty breast like in a juvenile bird.
When, separating Semipalmateds and Westerns this is easy because in this plumage Westerns has a noticeable amount of rufous on its crown, auriculars, and scapulars, which Semipalmateds doesn’t have. Also the streaking on a Western goes way down into the belly, while in a Semipalmated it barely passes the breast.
Structure
Even though I have discussed the plumage differences of these birds I will quickly discuss the structure differences of these birds.
The Least is the smallest bird with a small bill that is slightly drooped. Its posture tends looks as if it is crouching.
Semipalmated Sandpipers will be slightly larger than Leasts. Semipalmateds will have longer wings and a heavier, straighter bill.
Westerns will be a tad larger than a Semipalmated, and its bill will be larger and more drooped. Also, proportionality the Western Sandpiper will look very heavy with a large chest compared to that of a Semipalmated.
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Western Sandpiper (Photo credit: Wikipedia)
Overall, I hope you now have a better understanding of the identification of Least, Semipalmated, and Western Sandpipers. Hopefully, you can put these field marks into practice this coming spring when these birds migrate through your area.
-Landon