Warning: Non-wader enthusiasts will find this excruciatingly boring.
Hi Trevor,
> 1. "DBPL do indeed lose their breastbands entirely during the winter."
> Whilst this may be true, the non-breeding plumage of the nominate race which
> we see in Australia is of short duration, covering the primary moult and a
> short period afterwards (see Shorebirds, Hayman et al). I am still seeing a
> semblance of a breastband on some birds and it is now May. No doubt birds
> lose their breastbands, and subsequently regain them, at different times
> throughout the austral winter, so it would be inadvisable to suggest that if
> a bird has a breastband in winter it is not a Double-banded Plover.
The above is obvious and goes without saying. However, it is well worth
elucidating in case anyone read it otherwise. The message is in fact that
you should not dismiss a small plover in winter as not being a
Double-banded, on the basis that it does not have a faint breastband. And
that is how the original discussion on birding-aus began.
>
> 2. "Furthermore, the Pizzey yellowish-buff head feature for the immature
> depiction is probably closer to an average non-breeding adult. .......... If
it is extremely difficult to separate
> immatures from adults, how can you say that the Pizzey illustration is of an
> adult, not an immature?
Let me rephrase that: it could be either, is the message I received, and
that Pizzey's depiction with the faint breastband is a bird in transitional
plumage from breeding to non-breeding.
>And are we disregarding the feature that in an
> immature the supercilium is larger and continues further behind the eye? I
> was interested to note last month that all of the birds I saw with a more
> pronounced supercilium were also those that had a more golden suffusion
> around the head.
I would be inclined to be cautious with this feature. There may be a
possibility of distinguishing early in the winter, but at what point does
this become merged with the adult? Is it a matter of weeks or months? Does
the supercilium change during the austral winter? I would need a lot more
expertise before I would be confident. So read this that I am not
questioning but will be watching carefully this winter. Does anyone know?
>
> 3. "Furthermore, I noticed that in the museum skins, almost every specimen
> had some pale fringing to the feathers on the back and upperwing coverts."
> Did you notice the colour of these fringes, as the adult is supposed to have
> a warmer colour than the buffy-white of the immature? Or are we saying that
> this also is a non-reliable feature?
I noticed particularly than the breadth of the fringes varies, and seems to
be inconsistent with head colouration. I could not see a pattern of head
colour with fringing, and remain cautious about using colour until I learn
more. I recall a couple of skins which were clearly very young and speckled,
but we are talking about a more advanced stage of immaturity here. I have
until now thought that the yellowish buff on the head indicated immaturity,
and need to rethink the whole thing. I actually feel as though I have had
the rug pulled from under me on Double-bandeds - not their identification,
but separating young from adults. I will take myself into a corner with
HANZAB and hopefully return with more confidence on the age separations, or
else accept that it is too difficult in the field.
>Also, I seem to remember you saying
> that you identify the Caloundra Double-banded Plovers on the basis of their
> pale fringes. This could lead to birds being mistakenly identified as
> Double-banded Plovers, as there are certainly both Lesser and Greater
> Sandplovers around at the moment with extremely visible pale fringes.
Yes, I was looking at them on Thursday, and was very careful with this.
Mistakes can certainly happen, especially when you are doing a long survey.
We had Lesser and Greater Sandplovers, as well as Double-bandeds, in front
of us. Usually or often you see a different body language in the
Double-bandeds, which I can not put into words. I recall one bird, with its
back to me, and no possibility of my distinguishing feather features. I felt
at first that it was a Double-banded - in fact I called it as such, but then
recanted, and it was a body language thing that caused me to pause. Then, at
distance, I had to decide whether it was Lesser or Greater. I forget now
which it was. Let no one think it is easy, because it's a minefield. We
often have to let some of them go as "plovers unidentified".
At the bottom line of age separation I would have to say that I am not as
brave as you. I will retreat on the age identification until such time as I
get better at this. All I can feel confident about right now is that if the
traces of a breastband are there, it is an adult.
Cheers,
Jill
--
Jill Dening
Sunshine Coast, Qld
26º 51' 152º 56'
Ph (07) 5494 0994
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