Brent Goose populations

WeBS treatment of Brent Goose populations:

Reports to 2010/11 - Dark-bellied Brent Goose, Canadian light-bellied Brent Goose and Svalbard Light-bellied Brent GooseBarnacle Goose.

Reports from 2011/12 - As above with the addition of  'generic' Light-bellied Brent Goose and 'generic' Brent Goose.

Detail:

Two subspecies of Brent Goose Branta bernicla winter in the UK, these being the Dark-bellied Brent Goose B.b.bernicla and the Light-bellied Brent Goose B.b.hrota.  Furthermore, two distinct populations of the Light-bellied Brent Goose are involved, the Svalbard population and the Canadian population.

Dark-bellied Brent Geese winter primarily in England, occuring in substantial numbers on sites from the Humber Estuary southwards on the East coast, along the South coast, and with smaller numbers being recorded intermitently at sites in Wales and Northwest England.  Birds from the Svalbard population of Light-bellied Brent winter principally at Lindisfarne where they number in the thousands, but are also recorded annually at other sites in Northest England and Southeast Scotland in smaller numbers.  Records of Light-bellied Brent further afield in the East of Britain are generally taken to be from this population.  The majority of Light-bellied Brent from the Canadian population visiting the UK during the winter are to be found in Northern Ireland especially on Strangford Lough which alone hosts about 80% of the UK total.  Smaller numbers of Canadian birds are also to be found on the North and West coasts of Scotland with occasional records from Western and Southern generally being taken to be from this population.

Although Dark and Light-bellied Brent are readily distinguished in the field, the two populations of Light-bellied Brent cannot be separated. Accordingly, most records of the latter refer simply to Light-bellied Brent.  When reporting Light-bellied Brent, WeBS allocates all records from counties along the East coast of mainland Britain to the Svalbard population and all other records for coastal counties to the Canadian population.  From the WeBS report for winter 2011/12 onwards, the few records received of Light-bellied Brent from land-locked counties have not been assigned to population.  Very occasionally reports are received simply recorded as Brent Goose.  Of these, those from Northern Ireland are assumed to be from the Canadian population of Light-bellied Brent, but otherwise they are not assigned to subspecies or population.  The inclusion in the WeBS report from winter 2011/12 onwards of 'generic' Brent Goose and 'generic' Light-bellied Brent Goose ensures all such records are reported.

WeBS allocation of records for reporting purposes:

Dark-bellied Brent Goose: all records reported as Dark-bellied Brent.

Canadian Light bellied Brent Goose: all records reported as Light-bellied Brent from Northern Ireland, and coastal counties of the North coast of Scotland (including Orkney and Shetland), West and South coast Britain and the Channel Islands,  Any records of unspecified Brent Goose from Northern Ireland.  Any records specifically reported as Canadian Light-bellied Brent.

Svalbard Light-bellied Brent Goose: all records of Light-bellied Brent from coastal counties of East coast Britain.  Any records specifically reported as Svalbard Light-bellied Brent.

Light-bellied Brent Goose (from 2011/12 onwards): All records reporting Light-bellied Brent and unspecified records of Brent in Northern Ireland.

Brent Goose (from 2011/12 onwards): All records of Brent.

WeBS reporting of annual trends:

  • Dark-bellied Brent Goose: Both annual and monthly trends are derived from WeBS data.
  • Canadian Light-bellied Brent Goose: Both annual and monthly trends are derived from WeBS data.
  • Svalbard Light-bellied Brent Goose: Both annual and monthly trends are derived from WeBS data.
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