72
©Wildfowl & Wetlands Trust
Wildfowl
(2013) 63: 72–89
Survival and dispersal in a newly-founded
temperate Barnacle Goose
Branta leucopsis
population
HENK VAN DER JEUGD
Vogeltrekstation – Dutch Centre for Avian Migration and Demography, NIOO-KNAW,
Droevendaalsesteeg 10, 6708 PB Wageningen, the Netherlands.
E-mail:
Abstract
Survival rates and dispersal were studied in a newly-founded temperate Barnacle
Goose
Branta leucopsis
population in the Netherlands using marked individuals. Birds
were ringed at three localities: two in the Delta area in the southwest of the
Netherlands and one in Fryslân in the north. Annual survival decreased during
2004–2012 from
c.
95% to
c
. 75%, probably due to an increase in hunting pressure
introduced to reduce the size of the population and its damage to agricultural crops.
A decrease in survival should lead to a decline in numbers in the population, but this
was not apparent from the summer counts. Natal dispersal was high: 56% of males
attempted to breed > 10 km from their natal site, and 38% at > 100 km from their
natal area. In females, these figures were 30% and 24%, respectively. A substantial
number of male Barnacle Geese most probably emigrate to the large population that
breeds along the shores of the Barents Sea, and the Dutch Barnacle Goose
population currently is a source, from which restocking of the Barent’s Sea
population takes place. Breeding dispersal was low. Disturbance of colonies may
influence dispersal as birds from one colony disturbed by foxes showed remarkably
high natal and breeding dispersal.
Key words:
annual survival, Barnacle Geese, breeding dispersal, hunting pressure,
natal dispersal.
Survival and dispersal are key processes in
animal populations that affect the rate at
which populations change numerically and
spatially, and the amount of genetic
exchange between populations. A good
understanding of these processes is of
particular relevance in expanding or newly-
founded populations of species, such as
geese, where human-wildlife conflicts or
other management issues might arise. These
processes are difficult to study because this
requires following many individuals over
long periods of time and over a large area.
The study of survival is possible within the
