grey duck

General birdwatching discussion, help with bird identification, and all other things relating to wild birds and birding in NZ that don't fit in one of the other forums.
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Adam C
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Re: grey duck

Postby Adam C » Thu Jan 10, 2019 2:48 pm

Super interesting Andrew. And this is the sort of thing I was hoping someone would reply with. It seems what actually makes a Grey Duck a Grey Duck is lost in the nether nether. BUT the Green speculum with the super fine white trim would seem to be their squadron insignia and I think that should be the starting point at the very least. Beak colour between sexes is an interesting idea too as is the much thicker eye stripe which is something I hadn't looked for.

I guess I just find it an interesting topic and I think its a really good one to throw back and forth. I guess I like the idea that the ONLY colour on a pure Grey Duck is GREEN...and anything else is mallard influenced but your above photos throw a big spanner in the works of that theory unless I cling to my belief that the NZ sub-species (not official) don't have no orange
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Jim_j
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Re: grey duck

Postby Jim_j » Thu Jan 10, 2019 3:54 pm

I think I read in Notornis or the NZ Birds magazine that Murray Williams was working on a publication re Grey/Mallards?
I must admit I've always thought Orange legs = Hybrid in the NZ Grey Duck but maybe not..?
Again how can you be sure?

As an example a few years ago I held some y/c parakeet which I got from a breeder - they had no red in the crown, small size, no marking behind the eye - if you were in the bush and saw them you would say y/c.
However when they bred some of the offspring had red patches in the crown - so I'm guessing there was r/c lineage in their somewhere and they were x?-generation hybrids?

cheers
Jim
Clinton9
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Re: grey duck

Postby Clinton9 » Thu Jan 10, 2019 5:55 pm

Sir Joseph Banks shot a Grey duck in New Zealand and painted a picture of Grey duck during 1777.
Its legs & feet were either greenish-brown or brown.
andrewcrossland
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Re: grey duck

Postby andrewcrossland » Fri Jan 11, 2019 8:06 am

Most field guide images and descriptions show White-fronted Terns with black legs - but look around outside at the moment and you'll see a proportion with reddish legs. This was something that people missed until recently...
Its the same shortly for adult Black-billed Gulls - leg colour changes briefly to red.
White Heron bare parts - same thing.......
Grey Duck too I'll wager???
andrewcrossland
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Re: grey duck

Postby andrewcrossland » Fri Jan 11, 2019 8:59 pm

Here's a pic of Grey Duck (Pacific Black) from Sulawesi: Legs look orange-tinged eh?

Pacific1.JPG
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And look at this lovely Grey Duck photographed in Australia - legs more obviously orangey......

Pacific3.JPG
Pacific3.JPG (73.21 KiB) Viewed 396 times


Pacific 2.JPG
Pacific 2.JPG (62.6 KiB) Viewed 396 times
andrewcrossland
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Re: grey duck

Postby andrewcrossland » Fri Jan 11, 2019 9:23 pm

And here's some examples of fieldguides that show orangey legs - none less than Madge & Burn, 1988, Wildfowl: An identification guide: Look at both standing and flight image.

Grey Duck2.JPG
Grey Duck2.JPG (108.78 KiB) Viewed 389 times


And, also Menkhorst et al. "The Australian Bird Guide", which on the plate below says that adult females are the ones that can have "dirty orange legs", and in the text they say: "legs and feet dull green-yellow to orange-brown, more orange in breeding condition...."

Pacific Duck oz.JPG
Pacific Duck oz.JPG (66.29 KiB) Viewed 374 times


So, my suggestion is that we're over-estimating the number of hybrid birds we see and under-estimating the number of real Grey Ducks because we collectively haven't realised that leg colour and bill colour can be variable without meaning this is a hybrid trait.

I have to re-read the paper/s on genetics with 4 simple questions (because the genetics and statistical stuff is well above my pay grade).

Q1. how big is the sample size?

Q2. is the sample biased to sites in settled districts and cities or does it also extensively sample wilderness areas and habitats that do not have large numbers of Mallard?

Q3. Does it include Pacific Islands, New Guinea, Indonesia too, or just Australia and NZ?

Q4. Does the analysis take into account the close relationship of Mallard, Grey Duck and relatives and take care not to attribute genetic similarity they actually share to hybrid genes?
Last edited by andrewcrossland on Sat Jan 12, 2019 10:39 am, edited 3 times in total.
andrewcrossland
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Re: grey duck

Postby andrewcrossland » Fri Jan 11, 2019 9:27 pm

And, just to put an even bigger spanner in the works!! - check out these flight shots of Pacific Black Ducks from Sulawesi and Flores - speculum colour!!

sulawesi a.JPG
sulawesi a.JPG (40.89 KiB) Viewed 388 times


sulawesi b.JPG
sulawesi b.JPG (53.09 KiB) Viewed 388 times
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Neil Fitzgerald
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Re: grey duck

Postby Neil Fitzgerald » Fri Jan 11, 2019 10:07 pm

andrewcrossland wrote:..
I think the bill colour and leg colour should be ignored, and more focus made on green supercilium


Well, now i'm really confussed. I ain't never seen one of those critters ;)
andrewcrossland
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Re: grey duck

Postby andrewcrossland » Fri Jan 11, 2019 10:09 pm

ha, ha, yep, ok, I'll just pop back in an edit that!!
Jim_j
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Re: grey duck

Postby Jim_j » Sat Jan 12, 2019 1:23 pm

Yes interesting.
But if there is that variability within the species can you ever be sure you are seeing a grey duck?
I don't know enough about genetics either but I assume a "perfect" green speculum could also occur in a hybrid bird - as could a grey bill or greenish brown legs?
Time I think to accept a single new species the NZ Grey Mallard....!
Cheers Jim

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