Hey guys, I am a little confused about these pacific black ducks. They seemed to be mates because every time I saw them, they were swimming together.
One of them was a normal looking PBD, but the other one was a bit different, it was a lot paler than usual, so I thought bay be a mallard hybrid, but this one was smaller than its mate, a mallard hybrid would be bigger. So this one I thought is the female, and normal bigger one is the male.
my other thought was maybe something called Isabelline plumage which means plumage is a tannish peach brown colour. But I've only seen that in penguins.
Any thoughts??
they both looks like pbds to me, i suspect it's just moulting.
that said hybrids are fully fertile and when backcrossed with one of the parent species over several generations can be indistinguisable so who knows. they can also cross with teals. plumage mutations like leucism of pure non-hybrid birds can indeed be confused with hybrids.
i believe in New Zealand where the PBD is extinct as a pure species, a colony of 'pure' birds where found which looked like legit pbd, DNA analysis revealed they still have some mallard genes (like 1/10th)
Mallard x PBD are not necessarily bigger than PBD, i've seen them smaller.
general rules for ID of hybrids with true mallard include less prominent black facial markings, hints of orange on bill and legs.
PBD x domestic farm mallards (which is what mallards in most of australia are) can produce a cornucopia of characteristics (pale birds, white birds, pied).
Indeed the PBD or Grey Duck as we call it here is probalby extinct here. Problem is many authors and texts still list them as common, so many are reported, but are basicly definity not them. I have never seen a PBD, although there are some extreamly pure birds at the local alpine lake.
The top bird there has some feathers that look much like mallard feathers.
Young Birder Age 14
Canon 40D + Sigma 120-400mm
i wonder if the hybrid new zealand birds could be considered a new species
interestingly the -now extinct- Mariana Mallard from the mariana islands in the pacific may well have been a hybrid species that evolved from vagrant colonisations of both PBD from Oceania and Mallards from the Northern Hemisphere, so the NZ birds may recreate it.
https://en.wikipedia.org/wiki/Mariana_mallard
Wild-type Mallards have been much less successful in australia than they have been in new zealand (though they are commoner in the south and may be increasing), probably due to climatic factors; the Mallard being unadapted to periodic drying up of wetlands common in much of australia and preferring cool temperate climates. Interestingly, in Tasmania Mallards and Mallard x PBD are common, I suspect some may have come from NZ (there is also some trans-tasman gene flow/migration between mainland Aus PBD + NZ Grey Duck populations, so transfer of additional hybrid genes into aust population is evitable, incidentally pure PBD vagrants in NZ would be a good tick!).
Most Mallards in southern australia are found on urban and semi-urban areas are derived from domestic liberations and constitute an array of breeds, I wouldn't be surprised if 20% of all urban PBDs in aus contain some mallard genes.
Interesting, thanks...
Tegan - Melbourne Vic.