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Case Summary for:
Submission No 207: Caspian Plover Charadrius asiaticus, Cleveland Bay, QLD, 23 November 1995. Verdict: Not Accepted This submission relates to a medium–small plover sighted in a saltpan situated behind mangroves near the mouth of Aligator creek, Cleveland Bay, Qld, on 23 November 1995. The bird was in view for a period of 5 to 10 minutes allowing the observer(s) to note: a shorter, rounder physique than likely confusion species such as Oriental Plover and Greater Sand Plover; a fine sharp bill with no blunt angles; a white, buff-edged facial pattern and white ring around the bill; a broad dark-brown eye-patch extending onto the brown of neck and emphasising a large (sic) broad supercilium that was broader behind eye; brown-grey upperparts with some fine buff edging to the mantle; a dark tail with hint of white at the edges (difficult to see); dark upperwing with narrow white wing-bar, broader at base of inner primaries; a broad, deep and uniform buff-brown breast-band extending from the base of the throat to the carpal joint; white belly and vent; wings crossing and projecting (c. 2 cm) well beyond tail-tip; olive or grey legs, with no visible hind toe and toes projecting beyond the tail in flight; white underwing coverts and dark undersides of flight feathers. The observer(s) expressed great confidence in their identification, having consulted a number of important identification references. It was recognised by all Committee members that many of the features mentioned in the description are consistent with the proposed identification as Caspian Plover, notably the broad supercilium, white underwing-coverts, broad and uniform buff-brown breast-band, narrow wing-bar and olive or grey legs; the observer(s) also profess familiarity with the relevant confusion species. Nevertheless, members were divided in their opinion, with those voting against acceptance commenting that some of the features such as the toes projecting beyond the tail, the shorter, rounder physique and even the primary extension and breast pattern could arguably equally apply to Greater Sand Plover Charadrius leschenaultii; that some important identification characters (e.g. underwing pattern and breast-band pattern - see below) lacked crucial detail. The final outcome of the committees’ voting process resulted in a split decision. The lack of fine detail of some critical features and a lack of field notes, photographs or corroboration from other observers being the primary reasons for non-acceptance. The Committee notes with interest a recently published photograph from Japan (Kanouchi et al 1998) depicting a first immature non-breeding Greater Sand Plover with a uniformly brown, slightly deeper than usual and seemingly complete breast-band somewhat similar to the bird described. This identification pitfall serves to reinforce the amount of detail required to confirm the identification of great rarities such as Caspian Plover. The committee acknowledges that this bird may well have been a Caspian Plover as claimed but in the absence of fuller details of some crucial identification characters relating to this very brief sight-record, the Committee is unable to accept the identification beyond all reasonable doubt.
References and Bibliography
Tony Palliser |