As I mentioned in a previous posting, I came across a pair of
contrasting stints at the Manly Wader Roost [SEQ] a week and a half
ago. I have learnt a bit in the process of determining whether the
bird is a Little or Red-necked Stint. If the bird were in full
breeding plumage, the identification process would be fairly
straightforward. However, the bird is in transition and has many
characteristics that are indeterminate.
I have forwarded the images to a number of birders - the responses are
evenly split between Little and Red-necked. Interestingly, two
commentators who are linked to the HANZAB section on Little Stints
have come up with differing conclusions.
Tom Tarrant has kindly set up "Mystery Stint" in the Ciconiiformes>
Scolopacidae section of ABID http://www.aviceda.org/abid/ for the
three photos I took. I have reduced the size of the first shot so
people can see the stint standing beside a much larger stint. The
other two images are full size. The images will be available for
viewing after Tom loads them onto the website.
To the pertinent characteristics of the stint in question.
I compared the size of the two stints using the first two shots - the
two stints adopt comparable stances in the separate shots, and since
neither they nor I moved in the intervening time, it is possible to
compare their measurements. According to HANZAB, the size range for
Little Stints is 12-14cm, while the size range for Red-necked Stints
is 13-16cm.
Measuring on the screen, I found that size ratio between the stints
was 1.22 [you can't do this with the ABID photos as I had to reduce
the size of the first shot]. By way of reference 16:13 is 1.23. So
if the larger stint is 16 cm, then the smaller stint would be 13.1
cm. If the larger stint is 15 cm, the smaller stint would be 12.3
cm. This means that if the stint is a RNS, then it is at the very
small end of the spectrum, while the other stint is at the very large
end of the spectrum. If it is a LS, then it is in the middle to small
section of the spectrum.
The bill shape would be at the finer end of the spectrum for a RNS.
As far as I can see, there is no apparent swelling at the tip of the
bill - RNS often have a bulbous tip.
The stint has a relatively smooth shaped head. Many of the RNS I have
photographed could be described as blockheads with noticeable cranial
ridges above their eyes. In contrast, the bulk of the LS photos I
have looked at are relatively smooth shaped. [That may be a
subjective assessment, but it is one feature that I can make out.]
As for the plumage, the bird has a mantle stripe consistent with a LS,
but it is not bright, so is not an ID clincher. More importantly, for
a bird with coloured "cheeks", its chin and throat are white. If it
is a RNS, then the colour change on its throat is significantly
lagging its cheeks.
Working on the assumption that the bird is 13 cm long, the chestnut
fringing on the tertials is 2.5 mm. HANZAB gives a figure of 1 mm for
the fringing on a RNS [p. 265 If there is a figure for LS in HANZAB,
I didn't find it.]
The scapulars have large dark centres, broad chestnut fringing and
white tips.
The lesser wing coverts are a dull grey-brown - presumably this would
be retained non-breeding plumage if the bird is a LS.
People are welcome to view the photos and post their conclusions on
BAus. I am particularly interested in the opinions of people who are
familiar with Little Stints in the field.
On a concluding note, based on photos taken in the UK I have come to
realise that the white wingbar often diffuses into the primaries of
Little Stints - contrary to the text in P&K [7th ed]. I had been
working on the understanding that I would be able to ID a LS in flight
based on the colour of its primaries, but I can see that is not case.
That's a classic lesson - I suspect that like myself, many birders
look for key plumage markers to make their IDs. However, for some
birds, plumage is an unreliable feature.
Regards, Laurie.
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