Fróðskaparrit - 01.01.2009, Side 190

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RINGING RECOVERIES OF HOUSE SPARROW IN THE FAROE ISLANDS
DURING THE YEARS 1963-2007
%
0 20 40 60
Figure 4. Life-span of Faroese house sparrows ringed
as nestlings or juveniles in their first autumn and
recovered as dead (n=52).
The total recovery of the house sparrow
found in present study was 10%, which is
high compared to other studies, reported
from neighbouring countries. In Norway,
only 1.8 % of 28,724 ringed house sparrows
recovered during the 19th century (Bakken
et al„ 2009). In Denmark the recovery rate
was 2.4% (Bønløkke et al„ 2006) and in
Britain and Ireland, only 1.5% of 411,478
ringed house sparrows were recovered
(Wernham et al„ 2002). However, differences
in landscape and topography make compar-
isons between countries difhcult.
In the Faroese ringing studies, the high-
est recovery rate was found for house spar-
rows ringed in Tórshavn in 2002, where the
recovery score was 59%. In this study, all the
sparrows were 'older than 1st calendar year'
when ringed, which also is the reason for the
particular high recovery rate of this age
group (36%), compared to other age groups
ringed (8% and 9%). Also in the recent stud-
ies in Sumba, the recovery rates were high
(17% to 29%). In all of these studies, there
were extensive field activities. In Tórshavn,
where 112 house sparrows were colour-
banded at seven different locations, it was
possible to track the individual birds, which
accounted for the high recovery rate (Eliasen
and Jacobsen, 2002). In Sumba, the ringing
studies were carried out during a period of
one month in August and September. In
these studies, house sparrows were caught
daily by mist nets, which gave recovery of
both newly ringed sparrows and of bird
ringed in the years before.
The life-span for the Faroese house spar-
row was estimated to be 1.3 years, in average.
Of those, ringed as nestling or juveniles in
their first autumn, one half were recovered
as dead within 4.1 months. This life-span is
comparable to Danish results, where 67% of
the house sparrows ringed as nestlings or ju-
veniles in their first autumn were recovered
dead within the first year and additionally
18% after two years (Bønløkke et al„ 2006).
Similar results were found for house spar-
rows ringed in Norway (Bakken et al„ 2009).
Of known death reasons, "killed by cat"
was the most common (18%).
This is lower than found in Norway
(26%) (Bakken et al„ 2009), but higher than
in Denmark (7%) (Bønløkke et al„ 2006). The
oldest house sparrow recovered in the Faroe
Islands was 9.9 years.
The oldest house sparrow reported in
Denmark was 18.5 years (Bønløkke et al„