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Tuesday, 4 November 2008

HOODED MERGANSER IN FIFE - A DISCUSSION OF ITS AGEING












































































Hooded Merganser, Tayport Pond, Fife, 26 October to at least 4 November 2008
All images taken by Edinburgh birder Kris Gibb











































































Captive Hooded Mergansers photographed at Slimbridge WWT (Keith Vinicombe)
Plate 1) juvenile in hand; 2) juvenile male (note pale eye colour); 3) first-winter female; 4) juvenile and 5) ADULT female
The ageing and sexing of Hooded Mergansers in autumn is notoriously difficult but summarised on this excellent website here -:
After much consultation and study, I believe the Fife bird to be an ADULT FEMALE
My decision was made after consulting North American experts, browsing a fabulous wildfowl website (which portrays upper and underwings of all Nearctic ducks), consulting the UK400 Club Identification Panel including Keith Vinicombe who stands as the Club's wildfowl consultant and after studying some excellent images sent in by Kris Gibb. I also consulted widely with those that have seen the bird (eg, Rab Shand, the Fife county recorder) and also with Birdline Scotland.

The bird in our view is an adult female, based on the brightness of the eye colour, the extent of yellow at the base of the lower mandible (which also extends on to the upper mandible) and the broadness, extent and brightness of the white greater covert bar. It also has a noticeable crest, although this feature is marginal as first-winters quickly attain a crest in their first autumn. Furthermore, the shiny black tertials have longitudinal white stripes within them, and the bird has broad and rounded tail feathers. Juvenile Hooded Mergansers invariably have just plain dark brown upperparts and flanks whereas adult females have much darker (often blackish) mantle, back and scapulars and much greyer sides (with varying amounts of grey in the face).
When roosting out of the water, the right leg appears to be slightly damaged, suggesting that it may have once bore a ring.
LEE EVANS
BRITISH BIRDING ASSOCIATION