Wednesday, 11 August 2010

The tiny two - or not (small/medium Canadas, again)

A brief resurgence of interest in small Canadas, well, just Mr Thrower commenting on the current tiny two resident on the Seton Burn, encouraged me to post their photos today, as per here (though presumably he will have taken some too, which will be a million times better!).

Further to the previous discussion on Lothian Birding, focusing on the smallest, which has been called Richardson's by others (when it appeared at Aberlady the winter before last) what now are these two? As is often the case despite a basic similarity there is a clear size discrepancy, but both are on the small side and not long-necked. In absence of particular plumage features like collars or gular stripes the key to ID seems to be head shape - whilst these two have a slightly more blocky head that your typical large Canadas the forehead is nevertheless sloping and not very steep, neither are the bills particularly stubby. Thus they don't conform to a stereotypical Richardson's, let alone Taverner's, so I make them parvipes, hence part of the standard "Greater Canada Goose" (and not tiny at all!). Would be most interested in any opinions to the contrary!

Two broken links in the Lothian BirdForum posts, Danny Grandstand's Richardson's/Taverner's photos and the Bothal, Northumbs, Richardson's. I still find the latter puzzling as in many respects it looks like the Taverner's on the previous link, and completely inconsistent with the stubby bill/steep forehead on some Richardson's photos there, but then I'm not an expert...

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