Thursday, January 17, 2013

North Duffield Aythya sp

An afternoon spent in the LDV was pretty successful, highlights being an Aythya sp (see below) a brief Green Winged Teal (that I didn't see!) a sub adult male Hen Harrier! (2 in 2 weeks in York after none at all last year!) 2 Bewick's Swans (one with yellow darvic on leg same as original 2 found by Andy) Marsh Harrier, Peregrine, lots of ducks and waders!

The bird is a first winter drake and on first look is a drake Scaup type (ie grey vermiculations on back, largely white flank patches) which is what I first called it as when I saw it. However looking at it in more detail I soon realised that it was no bigger than the Tufted Ducks and had a peak to its head (not what I'd expect from a Greater Scaup) so we started thinking along the lines of Lesser Scaup or hybrid.

Unfortunately by this stage the sun had dissapeared behind a blanket of cloud and the light was fading, the bird was present in the large patch of open water on the other side of the Carrs so probably nearly 1km away!

Prolonged viewing of the bird allowed us to note the following features

Obvious peak to the head set towards the back of the head (no crest)
Same size as Tufted Ducks smaller than the Pochards
Black on tip seemed to be visible from the side profile, but not seen when bird faced towards me(difficult to work out due to range). When compared with Tufted Ducks there was a lot less black, but I would not like to say if this soley was restricted to the nail or not
Slightly paler band on the bill around the nail, not clear cut like a Ring-necked Duck more faded
Vermiculations fairly obvious on mantle
Brown markings on rear of white flank patch

The wing pattern was not seen. It did a wing flap twice in the 3 hours that I watched it for but both times it was facing towards me and so I was unable to see if the white extended from the secondaries into the primaries.

So to break it down, it looks good for Lesser Scaup overall however there are 2 features that I want to see better before it can be clinched as one, the nail pattern and the wing pattern. Hopefully in better light tomorrow this will be possible. I will be there from early tomorrow, fingers crossed!

Didn't manage to get any photos due to light and distance but will try tomorrow.

Anyone with experience of aythya hybrids and distant Lesser Scaups please comment! Only drake I've seen was an adult at basically point blank range compared with this bird!

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