Hi David
Thanks for your posting I was just about to make similar comments.
Particularly about the colour changes in feathers.
Breeding plumage is very difficult to score and I often have debates between
various other researchers on what we score as 100%. There are so many variables.
Age of the bird seems to effect amount obtained, there is differences in a lot
of species between sexes and even individual variation from year to year.
Regarding no such thing as 100% plumage I also agree in most respects. It
depends on what your scoring system would be. Do you score what 100% would look
like for an Australian bird before it leaves? Do you score it as what 100%
would look like say in late may in the Yellow Sea or do you score it on the
breeding grounds as 100% as if its breeding then thats 100% plumage for that
individual that year.
Cant say I agree with all the above but they are some of the arguments ive been
involved in.
So most researchers have there own personal scoring system when it relates to
monitoring individuals and recording how much breeding they obtain over the
course of a season.
I personally score in percentages of 25% so for example when I say 100%
breeding for a bird it may not be 100% but is closer to 100% than the score of
75%.
I also record a separate scoring system for the Red Knots that I work on in
China. I record percenatge on the mantle/back areas as a percentage and belly/
flanks and under tail coverts as another.
Breeding plumage is not easy particularly if you have not seen many individuals
in breeding plumage or are not familiar with sexes or subspecies.
Keen to know where the Black-tailed Godwit photo on the post was taken because
my gut feeling is that its not even our flyways subspecies because that plumage
colour doesnt suit our birds at all.
Happy to be proven wrong though.
Cheers Adrian Boyle
On 23/03/2011, at 8:46 AM, David James wrote:
> Hi Chris & Chris,
>
> At the risk of splitting feathers, it is a bit more complicated than that:
>
> Tringine and Calidrine waders like godwits and knots do not moult their
> flight feathers in the pre-breeding moult. Pre-breeding or pre-alternate
> moult is partial. In Black-tailed Godwit, the partial moult to breeding
> plumage involves head, neck, mantle, scapulars, underparts and all, some or
> no tail. However, they usually retain 10-50% of old mantle and scapulars in
> males and 20-60% in females (see Handbook of the Birds of the Western
> Palearctic Vol 3). So there is no such thing as 100% breeding plumage. Black
> colours do not get blacker or reds redder as the moult progresses. More new
> feathers with black or bright red grow in, increasing the percentage of new
> feathers and the amount of bright colours. In some cases (knots and stints
> for instance, but not godwits as far as I know) have very thin white tips
> that soon wear off. This makes a slightly worn plumage appear overall more
> colourful than a fresh one, but it does not necessarily
> mean that a fresh bird has less breeding plumage than a worn one.
>
> The bird that Chris W photographed has quite a low percentage of new
> scapulars, whereas the comparison bird has a high percentage of new scapulars
> and even a few new wing coverts.
>
>
> --- On Wed, 23/3/11, Chris Sanderson <> wrote:
>
>
> From: Chris Sanderson <>
> Subject: Re: [Birding-Aus] Black-tailed Godwit in breeding plumage in Alice
> Springs
> To: "Chris Watson" <>
> Cc:
> Received: Wednesday, 23 March, 2011, 10:19 AM
>
>
> Hi Chris,
>
> Yes, birds often leave Australia nearly completely coloured up. I have a
> nice shot from Broome of a line of Red Knot in nearly 100% breeding plumage.
> More typical though is they reach about 60-80% before departing and
> complete the rest either on migration or at the breeding grounds. I believe
> how quickly the males colour up is part of how a female decides on a mate -
> it is a demonstration of their fitness. After all, on top of replacing
> non-essential feathers for breeding plumage they also moult all their flight
> feathers, nearly double their weight with fat storage and flight muscle bulk
> and complete a host of other physiological changes to be able to make the
> arduous trip. If you can do all that, and reach the breeding ground first,
> you probably get first pick of females and your offspring will have the best
> chance of completing the migration unassisted once you leave.
>
> Another point - I had drilled into me time and time again in Broome by
> visitors from the northern hemisphere that what we think of as "full"
> breeding isn't. They nearly always complete the moult after they leave.
> Your bird is a very good example, but in 100% breeding plumage the reds
> would be richer and the blacks blacker. A quick net search shows this:
> http://6000k.net/Birds/Black-tailed+Godwit.jpg.php as a fairly good example.
> I'd say your bird is in 90-95% colour which is really great to see! More
> of the back feathers will change to the buff colouration with the black
> spots and more of the face and breast will go deep red, but apart from that
> most of the changes have already happened. Probably more coloured up than
> any Black-tail I've seen before in Aus.
>
> Thanks for putting the photos out there.
>
> Regards,
> Chris Sanderson
>
>
>
> On Wed, Mar 23, 2011 at 2:13 AM, Chris Watson
> <>wrote:
>
>> G'day folks,
>> Had a nice flock of 6 Black-tailed Godwits at the sewage
>> ponds in Alice on Tuesday including one bird in quite spectacular plumage.
>> I've stuck some pictures up on the Birds Central blog if anyone would care
>> for a gander.
>>
>>
>> http://comebirdwatching.blogspot.com/2011/03/black-tailed-godwit-in-close-to-full.html
>>
>> Is this common for migratory birds to be getting close to full breeding
>> plumage before departure?
>>
>> Cheers,
>> Chris Watson
>> Alice Springs
>>
>> --
>> *BIRDS CENTRAL*
>> *Central Australian birding resource*
>> *Guiding, writing, and the latest site information*
>> *from Alice Springs*
>> www.comebirdwatching.blogspot.com
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