Duck breeding "plumage"

Shirley Cameron wrote "The duck are all in breeding plumage and are no doubt hoping the inland lakes will have some water in them so they can go north and breed.  The Blue-bills are living up to their name; the Freckled Ducks' bills are becoming red, the Aust. Shovellers heads are a striking slate blue. "

This is a very interesting observation and comment.  At this time of year you would expect male ducks to be in their eclipse (non-breeding) plumage.

Male Blue-billed Ducks have an eclipse plumage that is similar to the female. This is complicated by the birds age and social status.  I gather that there are quite a few Blue-bills at Werribee at the moment.  This would result in the older dominant males retaining a largely breeding type plumage although the blue bill may have lost some intensity of colour.  Despite all the research I've been doing while putting together a Recovery Plan for this species (and Freckled Duck) there appears to little information concerning the age and circumstances in which males retain breeding condition.  There are quite a few Blue-bills at Gum Swamp, near Forbes NSW, at the moment.  Interestingly, there seems to be a predominance of males.  The literature suggests that moult of Blue-billed Ducks is "relatively" straight forward albeit with a few complications.  What is being reported in the field, however, suggests that it is far from straight forward.

Shovellers also have an eclipse plumage superficially similar to the female. Again, while the literature implies this is straight forward I suspect it is far from the case.

Freckled Duck have a very subtle eclipse plumage with only minor plumage differences.  The main difference between males in breeding and non-breeding condition (as most would be aware) is the red base to the upper mandible.  As with just about everything bird related, this is not clear cut.  Males can have a red bill and NOT be breeding.  If you think about other bird species, many attain breeding plumage but don't actually breed (fairy-wrens being a good example). The red bill of the Freckled Duck can be retained as long as five months.

Now, to the point I find really interesting (sorry if I'm babbling on a bit).  If these ducks at Werribee are in breeding plumage (bear in mind, however, that the brightness of the heads of the shovellers might simply imply freshly moulted feathers and that some red can be observed on male Freckled Duck regardless of breeding condition) where are they going to breed?  Most of the inland wetlands that support the majority of our breeding ducks are dry.  It's possible that some of the coastal wetlands have water in them but even so these are generally not used by the three species mentioned.  Timing is also an issue.  Blue-billed Ducks are largely seasonal breeders on large permanent wetlands.  While  Freckled Duck & Shovellers  will respond to inland flooding they are also largely seasonal breeders, although not tied to this as Blue-bills.

Shirleys observations are interesting and I hope she reports again if these ducks move further into breeding condition.

Cheers

David Geering




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