I’ve been very lucky (especially for a Brit birder) to have had the opportunity to look closely at a good number of Nearctic shorebirds in the last few years, and I thought it may be useful to look at one species that I’ve seen particularly well - the world’s smallest shorebird, the Least Sandpiper Calidris minutilla (it may just be that the photos I’ve taken of Leasts are better than the ones I’ve taken of eg Western Sandpipers C. mauri, but I’ll leave you to speculate on that…)

Least Sandpipers really are well named and clearly smaller than other stints/peeps in direct comparison, and in my experience one of the most approachable - keep reasonably still and a group of foraging Leasts will make their way right past you. Small-headed birds with short wings and slim, slightly curved bills (like all shorebirds females have longer bills than males so that they can exploit slighty different food sources and are not in competition with each other), Leasts are also one of only three small shorebirds to have yellow legs - the others being the East Asian Long-toed Stint C. pusilla and the Eurasian Temminck’s Stint C. temminckii: I don’t have enough photos yet to illustrate the differences, but Long-toed Stints are long-necked birds with upright stances and ‘pot-bellys’, and Temminck’s are drab birds with virtually no supercilia and long wings with a clear primary extension (a measure of how far the primaries extend beyond the tertials).

I’ve not been fortunate enough to get close enough to a breeding-plumaged Least to photograph one yet, but - given the time of year - it’s better to look at late-summer to late-fall birds anyway…

Non-breeding. Bolsa Chica, California, December.
Note yellow legs, lack of primary extension, small head, and short bill that tapers to a fine point.

Many birders dread trying to identify stints/peeps, but Leasts are actually one of the easier of the group to identify. Apart from their yellow legs, they are so small and typically crouch so low that they almost look like feathered mice scampering along the water’s edge. Unlike larger shorebirds they’re so short-legged that they rarely venture beyond the shallowest water and are often found picking small flies from mats of vegetation. Leasts show virtually no primary extension at all and often appear ‘neckless’ with tiny heads giving them a distinctively ’round’ shape at times - though of course alert birds will stretch if they’re looking for danger. These and other features are referred to again in the photos below

Worn adult. Jamaica Bay, July.
Note dark tones, heavily worn wing coverts, dark streaks on chin, and remnants of chestnut-toned ear coverts.

 

Worn adult. Alviso,California, August.
Note dark tones and heavily worn wing coverts. This bird looks relatively long-billed to me and is therefore probably a female.

 

Worn adult. Alviso, California, August.
Same bird as above. Note how the primaries (normally hidden or ‘cloaked’) can be seen under the heavily worn tertials.

 

Freshly-moulted juvenile. Bolsa Chica, California, September.
Every wing covert feather is fresh with fine white fringes.

 

Moulting (presumed) adult. Bolsa Chica, California, December.
Heavily worn and in moult.

 

Non-breeding (presumed) adult. Bolsa Chica, California, December.
Overall dark tones and worn coverts and tertials presumably point to non-breeding adult. Note how the white shaft of the longest primary is plainly visible now that the tertials aren’t cloaking it.

 

Non-breeding. Bolsa Chica, California, December.
Note uniformly fresh appearance. Feeding birds don’t normally form large, tightly packed flocks, but tend instead to form loose, mobile groups that spread themselves out along muddy edges or along muddy/sandy banks.

 

Non-breeding. Bolsa Chica, California, December.
Note uniformly fresh appearance. Leasts have a distinctive ‘jizz’, typically standing in a crouched position, “knees” (tibia-tarsus joint) bent sharply and body held close to the ground.

 

Non-breeding. Bolsa Chica, California, December.
Note uniformly fresh appearance and lack of primary extension beyond the fresh (long) tertials. In comparison with the top two photos - of worn adults - note that the primaries are barely visible at all (ie they are ‘cloaked’ by the tertials).

 

Non-breeding. Bolsa Chica, California, December.
Note that all stints have long toes, but in a similar view the foot of a Long-toed Stint C. subminuta would look almost gallinule-like!

 

Non-breeding. Bolsa Chica, California, December.
Least Sandpipers have fairly indistinct supercilia that don’t quite meet over the bill.

 

Non-breeding. Bolsa Chica, California, December.
Taken on the same date as the preceding seven photos above, the wing coverts of this bird are notably more worn than the other birds. I’m not sure why, but would be interested in any comments.

 

Bolsa Chica, California, December.
Leasts in flight look tiny and almost headless (they’re sometimes described as ‘bat-like’). Not the most useful of ID photos but I think almost surreally beautiful nonetheless…

 

Photographs copyright Charlie Moores