1990-2 - Dutch Birding

The enigmatic Cooper's and Coxs Sandpipers
They differ from C melanotos by having features that can be construed as +ntermediate
between that species and C ferrugrnea . Compared with C melanotos, they have
a longer, more decurved, blackish bill with yellowish confined to the extreme base
of the lower mandible, olive rather than yellowish legs, a lighter pectoral zone,
broader pale fringes to the blackish-brown rump-feathers, and central ippertailcoverts
not black but whitish. washed grey-buff . and marked with blackish-brown
bars and chevrons: some scapulars of summer plumage have traces of the scapular
patterning of C ferruginea (Cox 1987) .
In extraordinary circumstances (Cox 1989b), Parker (1982) based a new species on
the two Australian specimens, naming it Cox's Sandpiper Calydris paramelanotos.
Subsequently, all Australian records of C . aipina were reviewed and found to be
unacceptable, excepl for one in northern Queensland in 1983 (Roberts 1983) . Many
were then referred to C paramelanotos (Smith 1984) and Marchant et al (1986)
stated that more than 20 sandpipers seen in Australia and thought to be a
'stereotyped' hybrid or C alpina are now generally believed to have been this
'species' . However, it is very doubtful that all were 'stereotyped' or the same as C
paramelanotos . Of Smith's (1984) 21 sightings of the 'new sandpiper', eight were
originally identified as C alpina, with some descriptions comparable to thal species,
and among the eight are two that he first described as C melanotos (Cox 1987) .
Therefore, some birds must have looked different from others in the field Many of
the remaining sightings lack detail or are undescribed and, as noted by Pringle
(1987), it is impossible to say with any confidence that all were the same as C
paramelanotos. Indeed, it is known that at least one closely resembled C cooperi
(Cox 1989a) .
comparisons with Cooper's Sandpipe r
Links between C cooperiand C paramelanotos were strengthened when in September
1987 a juvenile sandpiper was trapped in Massachusetts, USA, and identified as
C pararrtelanotos (Buckley 1988, Kasprzyk et al 1988, Vickery et al 1988) No valid
reasons were presented to show why it was not a juvenile of C cooperi (Cox 1989a),
which is undescribed and which, perhaps, might have been expected in that
geographical region . Nevertheless, study into the taxonomic status of C,oaramelanotos
had become inextricably concerned with C cooperi.
It is important to realize that the holotype of C cooperi is in a transitional stage of
plumage growlh and does not display a definitive plumage phase (contra Ridgway
1919) . It was moulting from winterto summer plumage when collected like ooth types
of C paramelanotos (Cox 1989a) . While. in all respects, both C paramelanotos
appear to be intermediate between C ferruginea and C melanotos, C cooperidiffers
by having many characters intermediate between C ferruginea and Sharp-tailed
Sandpiper C acuminata - the reputed closest relative of C melanotos (Marchant et
al 1986) .
The ventral markings of C cooperi, in particular, are almost the same as those
displayed by specimens of C acuminata in a similar stage of moult (Ccx 1989a) .
When examples of C acuminata are moulting into summer plumage, their ventral
plumage initially appears quite spotted like C cooperi. At first the new feathers of the
breast are pale buff with dark brown spots or blotches in their centres, which torm a
diffuse spotted gorget across the breast . These markings extend along the sides to
the flanks but peter out towards the white belty, below which the underta l-coverts
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