Wednesday, 26 January 2011

Wild Goose Chase?

Quiet isn't it? Certainly a lack of passerines around. The past four days have seen me variously year ticking Red-breasted Merganser and Little Grebe whilst feeding the ducks with the kids on Sunday at Druridge Bay Country Park. Monday found me staring at Canada Geese but more on that later, whilst Tuesday added Nuthatch and Long-tailed Tit, the latter bizarrely along the promenade from North Shields Fish Quay at the Black Middens. A drake Goosander on the Wansbeck at Sheepwash bridge continued the momentum today as did three adult Gannets flying north off Newbiggin during an early afternoon seawatch.

Back to the Canada Geese; with Bothal Pond ice-free a portion of the regular Canda Goose flock has returned, perhaps 70-80 individuals. I don't think it is the whole flock by any means as there were more at the new lake at the old Stobswood Opencast as well as a dodgy looking pale hybrid before the snow so part of the flock still seems to be elsewhere. Given that it was either count the Wigeon again or look at the geese, I chose the geese and decided to have a look for anything odd amongst them. Without camera on Monday I came across an individual that had a solid dark throat line separating the two white cheeks which were much narrower than any of the other birds present. Tuesday armed with camera and more time, I found two similar looking individuals, at least one of which was perhaps 10% smaller than most of the canadensis present.

As you can see from the above, this individual is smaller with a different head shape, slightly greyer breast and some contrast between upperparts and flanks (as compared to the other 'normal' individual). The second bird suffering from a pronounced limp causing it to feed at least some of the time on it's belly has a similar cheek patch and greyer tone to the breast.
It also lacks any white between the mantle and black of the lower neck. I don't see any size difference with this one at all.So I started to re-read some of the recent on-line material about 'White-cheeked Geese' and races, and I dug through almost every field guide I have and whilst initially thinking that these might be showing characteristics of one of the interior races came away feeling perplexed that descriptions of many of the various races of Canada Goose are simply poor.
Obviously these are unlikely to be vagrants, I suspect the nearest they have, or will ever get to Canada, will be stepping over an empty bottle of dry gin. Picking a better brain than mine the suggestion came that either the small size and small cheek patch could be age related and these could be young birds, "watch them for two years and if it moults out it it's age related" came the dry reply. The alternative suggestion is that it is polymorphism (don't worry I had to look it up too!). If anyone else wants to chip in with suggestions or comments feel free, if not expect an update in about 1 year, 11 months and 28 days.

3 comments:

Stewart said...

Neither wonder there arent any comments!

alan tilmouth said...

There are now, anyway shouldn't you be signing autographs now you're sponsored by Birdwatching Mag? ;)

Stewart said...

Eh, what are you on about? Birdwatching Mag?? Email me the crack...