Pacific (not quite) Black Duck

[Denis Wilson <>]

Martin's "not quite black" Pacific Black Duck does not appear to have orange legs (the top of one leg is partially visible), nor curled tail feathers - the straight tail feathers are clearly visible. Those are both features Philip rightly asserts as signs to look for,

Size is not mentioned.  It is apparent from Martin's image that the regular Black Duck on the right, and the odd bird on the left are of the same size. Many Mallard crosses are as much as 50% larger than PBDs,

So some form of colour variant (not a hybrid) would appear to be the more satisfactory explanation, in my opinion. 

I acknowledge that hybridisation does seem to occur very readily and so presumably partial hybridisation (cross-back) could dilute the traits we look for in "Mallard crosses". But in the absence of the standard tell-tale hybrid PBD X Mallard signs, I prefer the albinism or partial albinism theory.

Cheers
Denis Wilson

On Mon, Jul 18, 2011 at 3:37 PM, Philip Veerman <> wrote:

That is a curious one. I have not seen that or something like it before. All I see is your photo. Yes I agree it is one of these two options. I don't know how common partial albinism is in ducks but it looks more like your option 2 to me. I suggest this as it does not appear to show any mallard type features. In particular the face pattern is still complete for a PBD. Hybrids as far as I have seen before don't show that full face pattern. If it does have orange feet or the curly rump feathers or the mallard type colour patch in the wings or is bigger than a PBD should be, then I would go for the other option.

Ultimately I don't know how you would know the answer as it is a hindsight question.

 

Philip

 

 

-----Original Message-----
From: martin butterfield [
Sent: Monday, 18 July 2011 1:39 PM
To: COG List
Subject: [canberrabirds] Pacific (not quite) Black Duck

I apologise if the bird in the attached image has been a source of intense debate while I have been away (although it doesn't appear in the Archives ).  I was intrigued to see the very pale duck at Kelly's Swamp this morning.  Is this:

1. one of the many forms of hybrid between Pacific Black Duck and domestic waterfoul; or
2. an albinistic Pacific Black Duck?

While the other ducks (and a Black Swan) appeared totally unphased by the bird the Purple Swamphens took a strong dislike to it.  They chased it all around the small area of water visible, from Ardea hide amongst the Typha.

On the subject of Typha it could be suggested that the time for remedial action is about now, before the returning Reed Warblers etc start setting up nests in there.

Martin

-- 
Denis Wilson
"The Nature of Robertson"
www.peonyden.blogspot.com