| Case Summary for:
Submission No 359: Isabelline Wheatear Oenanthe isabellina,
Mt Carbine, QLD. 15-25 November 2002. Submitted by Dale Herter & Tony
Palliser. Verdict: Accepted Four overseas visitors, Dale Herter, Alan Grenon, Betty Grenon and Neil Chartier, first located this bird on the 15th November 2002. This extraordinary discovery is testament to the fine skills of these observers. Carol and Andrew Isles, birding guides at the nearby Kingfisher Park Birdwatcher's Lodge confirmed the find. It was last seen on the 25th November 2002 by which time many observers had seen it. Throughout its stay it frequented almost bare ground; a dry, dusty area, forming part of a sports ground and rodeo site grazed by cattle in the small township of Mt. Carbine, North Queensland. On behalf of the finders, Dale Herter submitted a BARC Unusual Record Report Form. This was adequate to confirm that the bird discovered was a Wheatear Oenanthe sp?, but insufficient to confirm its specific identity given the numerous possibilities. The bird was clearly a wheatear from its general appearance, colouration, size, structure and tail pattern. The submission by Tony Palliser included complete descriptions of the bird, its behaviour and environment, several excellent photographs and a thorough analysis. The committee was convinced by this diagnosis and their own research based on the description and photographs provided, that the bird was an Isabelline Wheatear O. isabellina as claimed, and that all other possibilities were eliminated. Two voting members also saw the bird. The characters used to arrive at this conclusion were: · Relatively large size and upright posture The single most important character listed above is the tail pattern (Beaman & Madge 1998). The claimants were aware that females of the Northern Wheatear O. oenanthe, particularly those of the large northern subspecies leucorhoa, can closely resemble Isabelline Wheatear and that fine detail is required to discriminate between the two (e.g. Jonsson 1992). In this case all the distinguishing characters were noted. Morphologically, these were the very broad cross-bar and consequently the short stem to the inverted 'T' on the tail, absence of dark centres to the median wing coverts and the wing colour similar in tone to the crown. Structurally, the long legs and short tail combined to create clearance between the tip of the tail and the ground in spite of its very erect stance. Its choice of habitat and overwhelmingly terrestrial behaviour are consistent with this conclusion (Cramp 1988; Jonsson 1992; Beaman & Madge 1998; Robson 2000). Members voted unanimously in favour of acceptance commenting that the
precise age and sex of this individual was difficult to ascertain, although,
one member suggested that the pale tips to the tail indicate that it was
a first year bird as shown in Cramp (1988).
· Beaman, M & Madge, S. (1998). The Handbook of Bird Identification
for Europe and the Western Palearctic, Princeton University Press,
New Jersey.
Tony Palliser |