UNIDENTIFIED SHELDUCK

There is an unidentified shelduck at Werribee's Western Treatment Plant.  The experts cannot decide what it is.

Unidentified Shelduck, photo by Ken Haines

Initially some people thought it was a female Paradise Shelduck from New Zealand.  Paradise Shelducks have turned up in Australia before.  I saw one at Lake Wollumboola in New South Wales in January 2016.  That was a male.  The theory was that the Werribee bird was a juvenile female transitioning to adult plumage.

Paradise Shelduck from Heather & Robertson's Field Guide to the Birds of New Zealand.

This possibility has been ruled out as the plumage is too uniform for a bird that is transitioning, which should show mottling with some dark immature feathers.

Unidentified Shelduck with Australian Shelduck, photo by Ken Haines

Another suggestion (apparently favoured by our local South African birders) is that it is a South African or Cape Shelduck.

South African Shelduck from 'Wildfowl of the World'

This is regarded as unlikely because this species is not migratory and South Africa is a long way away!

Unidentified Shelduck

The bird is moulting and we all eagerly await its new plumage.  It would be a shame to leave its identity unresolved or to have to regard it as a mutant Australian Shelduck because we cannot be sure.

Unidentified Shelduck