Náttúrufræðingurinn - 2000, Side 16

summer of 1999 the authors visited 170 of these
and found 39 of them to be occupied by breeding
foxes but we estimate that a total of 43^18 dens
were occupied. Thus the mean territory size in
the area was 12.1-13.5 km2, although the disper-
sion of dens suggests that territories were larger
in the southern part than in the northem part of
the reserve. Mean length of coastline ranged be-
tween 4.0 and 4.5 km/territory.
Prey remains at dens show that food habits
during summer varied from one area to another
within the reserve and were in accordance with
the dispersion of bird cliffs and the amount of
debris, including carcasses, washed ashore by
ocean currents.
A comparison with hunting statistics for the
period 1991-1994 indicates that the number of
dens occupied by breeding foxes has increased
by less than 50% after protection. The number
of cubs alive in autumn is estimated at 172-192.
Possible causes of mortality during the first win-
ter may be accidents, such as falling off cliffs,
bite wounds and starvation. We estimate that
mortality between the ages of 4 and 12 months is
more than 10% and less than 50% and that, con-
sequently, 86-173 foxes reach the age of one
year. Taking into consideration the number of
territories becoming vacant due to the mortality
of breeding foxes, we estimate that 65-154 foxes
disperse from the reserve annually.
Other calculations, based on the recovery of
foxes which were ear-tagged as cubs within the
reserve in 1998, indicate that 57±56 of each co-
hort of foxes bom in the reserve are killed at
some stage by hunters in the neighbouring com-
munities. However, confidence intervals are far
too wide and these will only be narrowed with
an increased effort of ear-tagging within the re-
serve and a better understanding of natural mor-
tality in the fox population.
PÓST- OG NETFÖNG HÖFUNDA /AuTHORS'
ADDRESSES
Páll Hersteinsson
Líffræðistofnun Háskólans
Grensásvegi 11
IS-108 Reykjavík
pher@hi.is
Þorvaldur Þór Bjömsson
Náttúrufræðistofnun íslands
Hlemmi3
IS-105 Reykjavík
doddi@ni.is
Ester Rut Unnsteinsdóttir
Borgarhólsskóla
Skólagarði 1
IS-640 Húsavík
foxdog@snerpa.is
Anna Heiða Ólafsdóttir
Hafrannsóknastofnuninni
Pósthólf 1390
IS-121 Reykjavík
peli@vortex.is
Hólmfríður Sigþórsdóttir
Líffræðistofnun Háskólans
Grensásvegi 11
IS-108Reykjavík
isaksolvi@isl.is
Þorleifur Eiríksson
Náttúrustofa Vestfjarða
Aðalstræti 21
IS-415 Bolungarvík
nv@isholf.is
142