A WEB-FOOTED SANDPIPER

By Tom Ennis

July 2012

Last Autumn many Irish birders were given the opportunity to familiarize themselves with a fine

selection of the smaller American sandpipers at Tacumshin in Co. Wexford. Birders from Northern

Ireland were not slow to take up this opportunity to get to grips with the finer identification points

of those delectable creatures known to American birders as “peeps” and it was good to hear the

enthusiastic tales of success from those who made the journey. For my own part I was delighted to

catch up with the smallest of all waders, the Least Sandpiper Calidris minutilla. I had been hoping

to add this major rarity to my Irish List for over 20 years, having been thwarted at a twitch at

Ballycotton by others in the car I was travelling in, anxious to “get home at a decent hour”. Seething

all the way home to Holywood, Co. Down from County Cork does little for one's regard for one's

fellow man, so days of snarling at work colleagues and cat-kicking followed. Over the ensuing years

I have seen hundreds of Least Sandpipers in the USA. However enjoyable such experiences were

they did little to assuage my hunger for an Irish tick, so when I finally caught up with the tiny

morsel last September at Tacumshin, scuttling between the legs of the heftier Little Stints Calidris

minuta and Semi-palmated Sandpipers Calidris pusilla, my joy was boundless and all felt right with

the world. No cats were harmed during the course of this euphoria.

 

I feel that you might appreciate seeing a picture at this stage so here is my photograph of a typical,

brightly plumaged juvenile Least Sandpiper with its characteristic yellow legs well illustrated. This

image and many of the others appearing in this essay were obtained at the East Pond at Jamaica

Bay, New York. Only another stop and a fifteen minute walk from JFK Airport on the A Train (cf

Duke Ellington), this is a must-see destination for wader (shorebird = American) enthusiasts visiting

the Big Apple in Autumn (Fall = American). When birding in the USA its advantageous to speak

American.

 

But something else gave me a great deal of pleasure and that was renewing acquaintance with

another American “peep”, the Semi-palmated Sandpiper. A rarity itself, in Ireland, the numbers last

year were remarkable. The mixed group accompanying the juvenile Least Sandpiper contained 8

Juvenile “Semi Ps” (as they are known to Irish Birders) and I spent a good deal of time comparing

and contrasting them with the brighter-plumaged (dare I say handsomer) Juvenile Little Stints, also

present in goodly numbers. The birds were reasonably confiding and allowed close approach except

for occasional sallies into the wader flock by a hunting Merlin (or Merlins) causing them to “spook”

but thankfully to resettle after a panic-stricken bout of flying. Careful study showed some of the

finer identification points of the Semi Ps and the birds were so close I could even distinguish the

small amount of webbing between their toes.

 

This partial webbing or semi-palmation only occurs within the genus Calidris in two species: Semipalmated

Sandpiper and its close ally Western Sandpiper Calidris mauri. It does, of course, also

occur in certain other species. It was because of the partial webbing that these two small sandpiper

species were for many years separated from the rest of the Calidris sandpipers into a different

genus, Ereunetes. However this was rectified for ornithologists on this side of the Atlantic with the

appearance in 1940 of Volume III of the Handbook of British Birds. There the Semi-palmated

Sandpiper was assigned to Calidris pusilla (NB there were no British and Irish records of Western

Sandpiper then) and in a footnote H. F. Witherby stated “As the only material difference between

this and other species of Calidris is its semi-palmated foot this is not in our view sufficiently

important to warrant the bird's separation into another genus (Ereunetes)”. Over half a century later,

in the world of DNA profiling nothing has shown up to alter that view.

My first picture of a Semi P shows a juvenile wading through the salt marsh at Jamaica Bay and

although the feet are not visible in the picture, this rather brightly plumaged individual shows some

of the identification points which would separate it from a Little Stint, should you have encountered

a similar individual at Lough Beg or the Bann Estuary. The rather heavy, short straight bill, the

uniform scaled pattern on the upperparts, the well streaked cap, and the noticeable lack of the

“thumb prints” present on the sides of Little Stint's breast are all easy to see here. Being a “brighter”

type it also shows a sandy-red cap and upper scapular area.

My next picture shows a rather more typical Autumn juvenile. Plumage tones are a little duller but

this individual is sporting a rather thin white V on the upper scapulars. Not as obvious as that

present on juvenile Little Stints or juvenile Dunlins but still quite visible. But let's have a look at its

nearest foot, obligingly poised in tip-toe mode. The partial webbing is quite easy to see and is a

good clincher in identification. It will not be present on a Little Stint.

This juvenile Little Stint was photographed at the Bann estuary, Co. Londonderry in September,

1990. The richer plumage tones are at once evident, the bill is not as heavy as a Semi P's and

although the foot is not very well displayed there is no webbing visible. For a moment just give a

thought to the fact that these inexperienced little birds, hatched within the Arctic Circle only a couple

of months earlier, will make their way to wintering grounds in South Africa all by themselves

without the assistance of the adult birds to guide them.

A very handy head-on picture illustrates a further useful identification point. Because the bill does

not taper to a thin point the end often appears slightly bulbous. This impression is often increased if

the bird is feeding in very wet conditions when water droplets often adhere to the bill tip. A glance

down at the bird's advancing right foot and the partial webbing is clear to see once more.

Now compare the previous picture with this head-on view of the same juvenile Little Stint at the

Bann Estuary. As you can see the bill is noticeably finer and even though there is a drip at the end of

the neb, it doesn't give the bulbous end effect often to be seen on Semi Ps. This Little Stint is also

displaying the characteristic “thumb prints” on the sides of the breast ; all that's needed is for it to

display a non-webbed foot but I'm afraid it's the best I can do.

 

My final picture in this small series of Autumn juveniles shows another, rather ill-defined, white V

on a fairly typical fresh juvenile Semi P. This mark is not always noticeable on Semi Ps. In the

present instance it would probably appear more prominent on a distant view. However I wish to

draw your attention to the birds extended left leg, helpfully pushed forward out of the shadows. You

will observe that there is comparatively little webbing between the middle toe and the inner toe.

Previous pictures have shown the much greater amount of webbing present between the outer toe

and the middle toe. This is also the case with Western Sandpiper.

You will be very much less likely to encounter an adult Semi P in Ireland. Classically it is the

inexperienced juvenile waders which are more likely to wander off course on migration and Semi

Ps are no exception to “the rule”. As you will observe from my picture of a migrating September

adult at Jamaica Bay, it is by this time in very heavily worn plumage. This does not make

identification any easier and it is a pretty non-descript little bird. However you can see a few

features which will help. The thick bill and closely streaked crown can be seen and careful

observation would reveal a bulbous end to the bill and the semi-palmations on the toes. Also

noticeable are the random, ill-defined blackish spots on the upperparts which are remainders from

its summer plumage.

On the subject of summer plumage my next picture taken in May at Cape May Point, New Jersey

reveals an adult in breeding plumage. It's hardly comparable with the handsome breeding dress of

Knot, Curlew Sandpiper or even our familiar Dunlin but that's all you get for your money. Even its

close relative, the Western Sandpiper, puts on a better show. NB the blackish spots on the

upperparts which were still present on the worn plumage of the bird in the last picture.

Huge numbers of Semi-palmated Sandpipers migrate down the Eastern seaboard of the United

states every Autumn and continue on to Central and South America where they spend the winter.

Wintering birds are very rare in the USA. Western Sandpipers migrate down the Eastern United

States in smaller numbers but they do spend the winter in states south of New York and around the

shores of the Gulf. The two species are extremely difficult to tell apart in winter plumage and

provide an ID headache for American birders. However it is now generally accepted that a Semipalmated/

Western Sandpiper seen in the Eastern States in Winter is virtually certain to be a Western.

As you can see from my picture of a winter plumaged Semi-palmated Sandpiper, photographed in

Monterey, California, it looks quite unremarkable and not unlike a miniature winter Dunlin but the

webbing is just about visible on one sand-covered foot.

Top American birders find the calls of Semi Ps and Western Sandpipers useful in identification. I

must say that in the melee last autumn when the wader flocks were being so regularly harried by

Merlins, I found there was very little chance of distinguishing an individual call or assigning it to

any particular bird. However calls are well described in the Collins Bird Guide and I dare say those

diligent enough will be able to find recordings on an App for their mobile phone.

 

Birders may find these pictures, together with the image of a juvenile Semi-palmated Sandpiper I

submitted earlier to the Club Gallery (see Gallery Archive Jul to Dec, 2011) of use as most of the

identification points for Semi-palmated Sandpiper can be studied. Others who are very keen to be

on the look-out for this species in the Autumn with a view to carrying out their own ID may also

wish to consider making their own “pocket guide”. This would involve the sacrifice of part of a

Collins Bird Guide by cutting out the excellent Little Stint illustration by Dan Zetterstrom on page

153 and pasting or paper clipping it beside his Semi-palmated Sandpiper on page 165. With some I

know this shouldn't be too great a sacrifice considering the state their Collins Bird Guide is in from

constant good use. A nice new one will cost only £12:57 delivered free from Amazon.

 

Having broached the subject of literature, the 5 volumes of the Handbook of British Birds are a

treasure. I still refer regularly to my copy of this monumental work which was good old Sam

Penney's copy. Complete Handbooks sometimes appear on the second-hand market (I bought a

really good set locally,with dust covers intact, for £75:00 a few years ago but you'll be lucky to get

it at such a bargain price) and if you want to lay hands on a tip-top reference book then snap it up.

Don't let it go past you because you think a book published in the 1940's is outdated. The

information it contains is a hoard of ornithological riches.

 

So if this Autumn provides the chance for you to see a Semi P haste away and savour the

opportunity to enjoy this New World wanderer. If, after you have seen all of the main identification

features to your satisfaction, go in for a little closer examination and see if you can see the semi

palmations and where exactly the webbing occurs on the feet. You may not find this a particularly

easy exercise but amongst other things it will sharpen your ID skills and give you a lot more

ammunition with which you can bore your non-birding friends.