We (Rohan Clarke, Richard Baxter, Frank O'Connor and I) are back from Broome
where the Lesser Black-backed Gull was easily found and viewed. Before we
got there George & Jim had taken more photos from better angles, fuller
profile shots, which confirmed our judgements from the earlier images. While
we were there ca. 1,000 photos were taken notably by Rohan Clarke,
photographer extraordinaire, and nine of those are already in circulation
and will no doubt, soon be posted on his web site
http://www.pbase.com/wildlifeimages but I did not find them when I looked
this morning. Virtually all aspects are depicted.
Firstly for those interested in twitching this bird, the rubbish tip is in
the ominously named Buckley's Street (or Road), a ten minute drive from
China Town, Broome. Probably because we there on a Saturday morning when no
heavy vehicles were operating, there was no hesitation from gate control in
allowing us in. Note that we arrived at different times in 4WD vehicles and
were allowed to drive anywhere but wandering about on foot was not
permitted. Entry on week days and after rain may be more difficult and due
to the undulating nature of the site, the bird is unlikely to be easily
visible from outside the fence. The site was muddy with pools of water and
torrential rain that afternoon after we had left may have made it
impassable. The bird was present throughout our stay, often associating with
Silver Gulls. As previously stated, anyone experiencing difficulty should
contact George Swann. And don't forget that the Semi-palmated Plover should
still be around Broome.
Whilst this bird could easily be mistaken for a Kelp Gull, there are several
characters, some more subjective than others, that proclaim that this is not
a Kelp Gull. These include structural features such as general shape being
more gracile, smaller head, slighter bill as well as plumage features such
as more greyish tones to upperparts. The most convincing, measurable
features are the obviously longer wings projecting much further beyond the
tail and the moult stage.
The bird is one of two similar taxa, which according to the latest IOC
classification as adopted by BARC, are both subspecies of Lesser
Black-backed Gull Larus fuscus. These are the nominate fuscus (Baltic Gull)
favoured by some, me included although I oscillate, and the race heuglini
(AKA Heuglin's Gull) favoured by others. Most consider it too dark for the
race taimyrensis.
Expressing the moult situation in the manner set out by Nikolas in the email
below obscures important details. There are clearly two feather generations
in the primaries. Whilst slightly worn indicating that they are not fresh
feathers, p1 to p6 are much newer than p7 to p10, which are very old and
worn. Whilst this moult pattern does fit heuglini, it also fits fuscus so is
of little or no value in determining subspecies. Using the wing tip diagrams
in the Olsen & Larsson Gull book pages 26-32, the darkness of the primaries
is a better fit for fuscus, whilst the size of the remnant mirror on p10 is
a better fit for heuglini. I also feel that the total lack of dark streaking
on the head or neck that is supposedly a feature of winter plumage in both
contending taxa favours fuscus as that race has the least amount of
streaking.
Mike Carter
30 Canadian Bay Road
Mount Eliza VIC 3930
Tel (03) 9787 7136
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