Fróðskaparrit - 01.07.2004, Síða 79

KYKSILVUR í LIVUR, EGGUM OG FJØÐUR
CEPPHUS GRYLLE FAEROENSISIN THE FAROE ISLANDS
77
B.guillemot adult males
Fig. 3. Mercury in black guillemot adult male livers. The samples were analysed in pools consisting offrom 4 to
12 individuals. The data of January 1997 is the mean of two pools of7 and 6 individuals. Modified from Dam,
1998b.
from the lowest liver mercury at 0,21
mg/kg ww liver to 3,77 mg/kg (Olsen et al.,
2003). Testing with Mann-Whitney U-test
shows significantly higher liver Hg content
in adult females than in juvenile females
(P=0,05) while the difference between
adult and juvenile males and between
males and females was not found to be sig-
nifícant. When all adults were seen as one
group and compared to all juveniles, how-
ever, the difference was significant.
The variability is also reflected in the
pool results, where the lowest pooled liver
sample mercury concentration was 0,38
mg/kg and the highest was 0,97 mg/kg
(Dam, 1998b; Dam, 2000), with the highest
pooled liver sample mercury concentration
found in a group of juvenile males and the
lowest in a group of adult males.
Feather
For the purpose of determining whether the
concentration of mercury is the same in
body feathers plucked from the plumage at
two different sites and to determine
whether such samples are comparable,
feather samples were taken from 15 birds.
These 15 birds were taken at two different
locations (though separated by a few kilo-
metres only) and at two different times. The
majority of the birds making up the first
sample (n=8) were taken near Sveipur in
June 1996 and the second sample (n=7)
near Hestoy in August the same year. The
samples were taken of contour feathers
from two sites; from the back between the
wings and from under one wing, where the
latter is thought to be the best site, as it is
supposed to lead to a minimum of insula-
tion loss when feathers are removed from