The Greenland White-fronted Goose Anser albifrons flavirostris

Despite the morphological similarities to support
a recent New World origin for flavirostris, there is
no suggestion of regular wintering grounds for
White-fronted Geese in the eastern United States,
where flavirostris remains a rare vagrant (e.g.
Hewitt 1948, Parkes 1960, Finch 1973). At the
times of maximum extent of ice cover during recent
glacial periods, there were never land bridges
between west Greenland and Canada (Andrews
1982). It is also interesting to speculate how ancestral
Greenland White-fronted Geese originating
in North America came to have a Palearctic
migration system like that of the Old World
Wheatear Oenanthe oenanthe that also breeds in
west Greenland but migrates to Iceland to Europe
and Africa in autumn.
All of the potential theories relating to origins of
flavirostris suffer from weaknesses of one type or
another, and the available fossil and other evidence
simply does not exist to support or refute
these ideas. The current distinct feeding ecology
and habitat use of flavirostris, if long established,
would have restricted its distribution. The exploitation
of wetlands of a particular maritime type,
especially peatland formations, would have restricted
the race geographically to its current
world range on the mild western fringe of the
European landmass. The geographical, morphological,
behavioural and demographic characteristics
of the sub-species suggest its long separation
from other presently existing races, but confirmation
will have to await appropriate genetic
analysis embracing all the different forms identified
within the current Anser albifrons. Collaborative
analysis is currently well advanced to describe
the morphological variation in different
population elements (Ely et al. in preparation).
This will be the precursor to a major genetic analysis
(based upon an existing and growing archive
of blood samples gathered from around the arctic)
to establish more clearly the phylogeny of this
species and its various described sub-species.
2.3 Factors affecting the current
distribution
The present wintering distribution of the Greenland
White-fronted Goose is concentrated along
the northern and western fringes of Britain and
Ireland (Fox et al. 1994a, MS14). This distinctive
distribution mirrors the climatic template for the
formation of oceanic blanket bog. This habitat
formed the traditional overwintering habitat for
the subspecies before Man substantially modified
the landscapes of Britain and Ireland (Ruttledge
& Ogilvie 1979, Fox et al. 1994a).
The Greenland White-fronted Goose specialises
on feeding by up-rooting cyperacean species to
consume their nutritious lower stem storage organs.
In particular, the common cotton grass
Eriophorum angustifolium was, or is still, eaten by
the geese in Scotland, Wales, Ireland, Iceland and
Greenland (Ruttledge 1929, Cadman 1953, 1956,
1957, Pollard & Walters-Davies 1968, Madsen &
Fox 1981, MS2, MS4, Fox et al. 1990). This species
of cotton grass is common throughout Western
Europe, but thrives well where high rainfall and
a mild wet climate creates patterned blanket and
raised mire systems. Oceanic mires characterised
by such complex surface topography have welldeveloped
water- and Sphagnum moss-filled depressions.
Although not necessarily the optimum
conditions for the growth of E. angustifolium, such
wet peatland depressions facilitate the easy extraction
of the lower stem parts of the plant favoured
by the geese. In contrast, E. angustifolium
can be vigorous and abundant in more mineral
wetland soils, but in such situations, the belowground
plant parts are difficult or impossible to
extract by geese.
On the same oligotrophic bogland habitats, the
Greenland Whitefront also consumes the Whitebeaked
Sedge Rhynchospora alba, which overwinters
as small bulbils which are highly nutritious
and much sought after by the geese (Cadman
1953, 1956, 1957, Pollard & Walters-Davies
1968).
The Greenland White-fronted Goose is also confined
to an area of Britain and Ireland defined by
the mean January 3ºC isotherm (Belman 1981).
The low probability of prolonged ground frost
throughout the winter period within this range
is thought to be an important factor that permitted
the geese to extract the subterranean stem
bases of Eriophorum and bulbils of Rhynchospora
from the soft Sphagnum cuspidatum, S. auriculatum
and S. recurvum lawns (MS24). This theory is supported
to some extent by the fact that at least 4
flocks in Ireland and 1 in Wales became extinct
after the severe winter of 1962-63. In that winter,
daily sub-zero temperatures occurred continuously
in western Britain from 23 December 1962
until 6 February 1963 (Beer 1964). In that period,
Greenland White-fronted Geese were displaced
when their bogland habitats were frozen, and
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