on 9th I came across an interesting aythya duck at Barton that suggested Ferruginous Duck; I was slightly concerned about the extent of black on the tip of the bill although the bill was the right shape and dark grey with a pale wedge bleeding back from the black tip; the irides were pale but not the bright white of an adult male and the general plumage tones were dull mahogany and black compared to adult drakes; the undertail coverts had some greyish subterminal marks and the belly and lower breast were distinctly patterned with neat brown feather centres forming a streaked pattern on a creamy background; when the bird spread its wing and in flight the broad brilliant white wing bar stretching across the primaries and secondaries contrasted strongly with the blackish forewing coverts supporting identification as Ferruginous Duck; checking the key detailed reference on Ferruginous Duck ID in British Birds (if you are not a subscriber you should be) but all BB articles are now available online from the BB web site, revealed that the bird has no anomalous features and can be identified as a juvenile / first-winter drake Ferruginous Duck -- other features can be seen in my blog posts and some are detailed below;
the pointed tail feathers, spiky look to the tail, belly markings, brown lines in the white undertail coverts and the bill pattern plus the duller iris and general coloration all seem to point to ageing as a juvenile; an interesting thing I noticed in the photos of the bird wing flapping is the small white round spot under the base of the lower mandible; in The Ducks of Britain and Northern Europe, Gooders and Boyer, there is a little sketch of this feature and text that states a fleshy white spot at the base of the the underside of the bill is found in drake Ferruginous Duck,and also in Bauer's Pochard and Ring-necked Duck;
In the BB paper KV shows a first-winter male with more extensive black on the bill tip and in the identification section under bill pattern states the following:
1) a large black bill tip is perfectly normal on female and immature Ferruginous Ducks and would not in itself suggest hybridity 2)it is perfectly normal for juveniles to have a predominantly all-dark bill, until at least autumn or early winter
A good bird it engendered interest and research and is only the second record for the Barton pits following the adult drake on Waters' Edge in Feb - April 2001 -- it has been feeding almost constantly today possibly suggesting it is a recent arrival as numbers of Pochard and Tufted Ducks have increased in the last week
Identification of Ferruginous Duck and its status in Britain and Ireland K E Vinicombe British Birds Volume 93 Number 1 January 2000 pages 4-21http://pewit.blogspot.com/2011/10/ferruginous-duck.htmlhttp://pewit.blogspot.com/2011/10/when- ... inous.html
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