The Greenland White-fronted Goose Anser albifrons flavirostris

5 Pre-nesting feeding
5.1 Introduction
Lack (1968) was the first to suggest that laying
dates, clutch size and chick growth rates were coadapted
in birds to ensure maximum fitness. Laying
date is important, since in most studied goose
populations, goslings hatching earlier have a
higher probability of survival and recruitment
than those hatching later (e.g. Cooke et al. 1984,
Warren 1990). Female geese in good body condition
generally lay larger clutches and fledge more
young than females in poorer condition (Ankney
& MacInnes 1978, Ebbinge et al. 1982, Ebbinge
1989, Prop & Deerenberg 1991, Johnson & Sibly
1993, Warren 1994, Ebbinge & Spaans 1995).
Hence, there is considerable evidence to support
the idea that the ability of a female to accumulate
nutrient stores at the earliest stage prior to the
onset of breeding has a considerable influence on
her ability to reproduce successfully in a given
year.
For many years, it was considered that most arctic
nesting geese built up stores on the wintering
grounds, supplementing body condition at one
or more staging area on spring migration before
they reached the breeding areas. In the 1970s, the
weight of evidence suggested that most arctic
nesting geese bred immediately on arrival, or very
shortly after arrival, on their northern breeding
areas (generally as soon as nest sites were freed
from snow cover). Therefore, it was naturally assumed
that the internal nutrient stores remaining
on arrival to the nesting grounds were of considerable
importance in determining reproductive
success (Barry 1962, Ryder 1970, Newton
1977, Ankney & MacInnes 1978). However, it has
always been apparent that any supplement to the
reserves of a female goose on arrival at the breeding
grounds will maintain or improve her general
nutrient status and increase her chances of
reproductive success, as long as delay of first egg
date after arrival carries no cost. Theoretical considerations
suggested that, for the Lesser Snow
Goose Anser caerulescens caerulescens at least, the
fat stores available on arrival were only sufficient
to account for 46-70% of the lipid and 14-55% of
the protein requirements for clutches of 3-6 eggs
(Meijer & Drent 1999). From this standpoint, female
geese arriving at the breeding grounds have
to supplement stores with substantial amounts
of dietary fat and protein in order to attempt reproduction
at all.
As more studies have been carried out, it has become
more apparent that few arctic nesting goose
populations were truly capital breeders, in the
sense that all reproductive material invested in
clutches were derived from stores accumulated
by the female in areas remote from the breeding
areas. It is now widely recognised that many populations
exploit spring staging areas close to, but
not necessarily at, ultimate breeding sites and
hence have the potential to supplement stores
after the main spring migration and prior to first
egg date. Raveling (1978) was amongst the first
to recognise that many species of northern or arctic-nesting
goose regularly nested 10-13 days after
arrival on breeding areas, the period required
for rapid yolk development. This enables the female
goose to modify her timing of first egg date
and the investment in her clutch based on external
(e.g. weather, nest site availability, e.g. Carriere
et al. 1999) and internal conditions (e.g. extent of
stores, see Ganter & Cooke 1996).
It has since become clear that White-fronted
Goose populations in particular rely upon prenesting
feeding on the nesting grounds to supplement
stores for investment in reproduction
(Ely & Raveling 1989, Budeau et al. 1991). Other
species show the same response (e.g. the Lesser
Snow Goose, Ganter & Cooke 1996) including the
very high arctic Greater Snow Goose Anser caerulescens
atlanticus, thought originally to breed soon
after arrival on the nesting areas (Choiniére &
Gauthier 1995).
5.2Mechanisms for recouping body
stores on the breeding grounds
Amongst the first studies to demonstrate prolonged
pre-nesting feeding on the breeding
grounds was that of the Greenland White-fronted
Goose (MS1), where it was evident that geese fed
locally for the period of at least 10 days between
the first arrivals and the onset of breeding. Geese
fed on the highly nutritious roots and stolons of
Puccinellia deschampsioides, bulbils of Triglochin palustre
and the lower stem of Eriophorum angustifolium
and Carex spp., excavated from low altitude
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