A WEB-FOOTED SANDPIPER
By Tom Ennis
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 StintsCalidris
minutaand 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
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.