This small plover was photographed on September 17 2002; It must
surely be an adult, based on the deep, blackish breast-band; I
was able to study the bird very carefully via telescope - it had
no trace of a pale orbital ring; it's feet remained hidden the
whole time, and when it flew off it was silent; while there was
a white intrusion above the line of the gape, the area immediately
above the gape point was actually dark-colored; I had been seeing
up to six SEPLs at this same spot in the preceding days, but this
day there were no others for comparison - however this bird first
drew my attention because it looked much darker (and "colder")
than those I'd been seeing previously (also adults):
The bill was unlike anything I've seen on a Semip. Plover previously,
being slim and evenly tapering to a blunt point, with just a tinge
of dull orange-flesh at the base of the mandible:
The collage below is based upon the recent images at the excellent
resource for serious birders: Irishbirding.com
; it shows two local Irish Common Ringed plovers (juvs) with the
recent Irish juv. Semipalmated Plover, plus the Benbrook plover (an
adult), for comparsion:
NOTE: in the image above/below there is a shadow in the stone
behind the bill near the tip that is distorting the distal maxilla
shape:
Discussion (texts in quotes are from "Shorebirds"
by Hayman, Marchant and Prater):
I see varying numbers of SEPLs every season here in North Texas,
and I study all of them to learn their variations. I feel that
CRPL is a stealth vagrant throughout Norh America, given
it's breeding range and known vagrancy in Alaska and the NE seaboard
of North America. When trying to identify these plovers, it is
important to understand the geographical variations that are known
(and keep in mind that some variations may remain undocumented.)
I am unaware of any published data on geographic variation in
SEPL; given its fairly large breeding range, I'd expect there
to be some variation - maybe in bill structure - but I do not
know how this manifests itself. Two races of CRPL are recognized:-
nominate hiaticula breeds from "NE Canada to W Europe",
with tundrae occupying the rest of the range from northern
Scandinavia across Russia to the Chuchki Peninsular. While it
is generally held that tundrae is "smaller and darker
than the nominate race", it is vital to also note that "This
division is unsatisfactory in that there are clines in both size
and upperpart colour which run north-south rather than east-west:
the largest, palest individuals are in S. Britain and France,
and are much more distinct from tundrae than are nominate
birds from Greenland." - my underlining here, to emphasize
the caution needed when comparing images of SEPL to British CRPLs.
If the north-south cline in upperparts colour is found across
the entire range of both these plovers, then this might explain
the anomaly whereby CRPLs found at Gambell Island among commoner
SEPLs in May/June appear paler than the SEPLs, yet along the North
American Atlantic seaboard vagrant CRPLs appear darker than SEPLs,
and then in Western Europe unworn SEPLs are expected to look a
bit darker than CRPLs:- Perhaps the Gambell CRPLs are Spring overshoots
from the southernmost populations in NE Russia while the SEPLs
from NW Alaska may be among the darkest of that taxon; Conversely,
vagrant CRPLs seen in NE North America are likely from the most
northerly-breeding populations in this entire complex(northern
Greenland and northernmost Canadian islands), where they may be
seen among the most-southerly-breeding (palest?) SEPLs; Over in
Europe it is likely that the vagrant SEPLS come from more-northerly
populations on southern Baffin Island, and they are seen among
the southernmost CRPLs.
So, when comparing photos used in ID articles (e.g. BIRDING, Vol.
XXV: No. 4, Aug. 1993 - Dunn; BIRDING WORLD, Vol. 10 #6, June
1997 - Lakin, Rylands et al.) it is critical to stay aware of
which "types" of each species you are comparing.
To get a feel of how different the two races of CRPL can appear,
look at Dick
Newell's CRPL images depicting presumed hiaticula and
tundrae together; given that BWP describes quite distinct
moult strategies for these forms, IDing some individuals of CRPL
may be easier than IDing a SEPL from CRPL!
I also recommend looking at this
plover from southern California(especially its feet); another
challenge to our understanding of these forms.
