Fróðskaparrit - 01.01.2004, Síða 268

266 RECOVERIES OF GANNETS (MORUS BASSANUS) RINGED IN THE FAROE ISLANDS
6000
5000
4000
3000
2000
1000
0
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
No. of Gannots
♦ Autumn ■ Winter ▲ Spring X Summer
Fig. 2. Distance
between ringing and
recovery locations
according to season,
when the Gannets
vvere recaptured.
of the Gannets were recovered within one
year after ringing, while approx. 30% were
recovered more than one year after ringing
(Fig. I).
Most recoveries (61%) are from the
autumn and winter, while 39% are from
spring and summer (Fig 2). The mean dis-
tances, between ringing location (Faroe
Islands) and the place of recapture, during
the various seasons are approx: 2,020 km in
autumn (n=13), 3,090 km in winter (n=8),
1,560 km in spring (n=4) and only 20 in
summer (n=2).
There is a significant difference in dis-
tances between ringing and recovery loca-
tions during winter and summer, p=0.012
(ANOVA, Tukey's Post Hoc test).
Most recoveries abroad were during au-
tumn and winter, while the 9 recoveries
on the Faroe Islands were evenly distribu-
ted over the year, with 3 recoveries during
spring, 2 in summer, 2 in autumn and 2 in
the winter (Fig. 3). In order to distinguish
between the recoveries from the Faroe Is-
lands these are shown with a colored dia-
gram rather than with overlapping circles.
The height of the columns in the diagram
indicate number of Gannets.
The younger Gannets (1-2 yr) were re-
covered a mean distance of approx. 2,190
km from the ringing location, while Gan-
nets 6yr or older were recovered at a mean
distance of 1,420 km from the ringing lo-
cation (Fig. 4). However, the difference is
not significant, p=0.655 (ANOVA). Age
groups 3yr and 14yr are not included in the
statistical test, because n in each group was
too low for the test (n=l).
Discussion
As Fig. 1 shows most birds were recovered
within one year after ringing (Fig 1). That
most birds are recovered a relatively short
time after ringing is a common pattern be-
cause the younger birds are more inexperi-
enced than the older ones (Barret, 1988).