13 December 2013

Brent Geese in Glamorgan

(c) P. Croft
Philip Croft's photograph of a family group of Pale-bellied Brent Geese at Port Eynon last Sunday prompted me to look at the relative abundance and distribution of the two regularly occurring subspecies in our area:

The nominate Dark-bellied Brent Goose (Branta bernicla bernicla) is by far the most frequent race with numbers wintering in the Burry Inlet usually peaking around the 900 mark in the last five years (see plot below: Gower Ornithological Society data), although a maximum of 1,680 was recorded during the 2005/6 winter. These birds breed along the Arctic coasts of central and western Siberia.
The Pale-bellied Brent Goose (B. b. hrota) is much less frequent and singletons or small family groups are the norm, quite often separate from the larger flocks of Dark-bellies. Pale-bellies are also more likely to be seen outside of the Burry with Swansea Bay a favourite spot, however, these birds rarely stay around too long, presumably due to higher levels of disturbance at these sites. The breeding range of Pale-bellied includes Franz Josef Land, Svalbard, Greenland and north-eastern Canada.

There are only two occurrences of Blank Brant (B.b. nigricans) in our area, both birds overwintering with Dark-bellies in the Burry/Whiteford. The breeding range extends from north-western Canada, across Alaska and in to eastern Siberia.

Next time you chance upon some Brents away from the Burry, see if their bellies are pale or dark and it will give you a greater appreciation of these long distance travellers.

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