Fróðskaparrit - 01.01.2009, Side 91

Year'round video surveillance of individual
nest'site attendance of Northern Fulmars
(Fulmarus glacialis) in the Faroe Islands
I eitt ár i/órðu reiðurstaðir hjá havhesti (Fulmarus glacialis) /
Føroyum eygleiddir við vakmyndatóli
Jóhcmnis Dcmielsen1 and Sven-Axel Bengtson2
1 Department of Ecology, Lund University, Sólvegatan 37, SE 223 62 Lund, Sweden.
johannisdanielsen@gmail.com
2 Museum of Zoology, Lund University, Helgonavágen 3, SE 223 62 Lund, Sweden.
sven-axel.bengtson@zool.lu.se
Abstract
Nest-site attendance was monitored on a year-round
basis by using video surveillance cameras at 10 poten-
tial nest-sites in a small colony of Northern Fulmars
(Fulmarus glacialis) in the Faroe Islands. In the colony
27-34 nests-sites were occupied each year; 25-38%
contained egg and 0-10 young were fledged.
Altogether 40 potential nest-sites were identified
during the course of the study (2004-2007) 18 of
which were actively used for breeding (i.e. egg-laying)
in 1- 4 years. Although few birds were marked and
individually identifiable some cases of change of
Partner and/or nest-site were shown to occur.
Successfully breeding pairs departed the colony at the
end of August or early in September, whereas those
that lost eggs in June left earlier though stayed for
several weeks before leaving; hence, individual length
°f post-breeding absence (coinciding with primary
tnoult) varied between 105and180days. Firstarrivals
tnostly occurred in second half of December, though
ac this time of the year the nest-sites were only
mtermittently attended with considerable individual
variation. During the pre-breeding period nest-site
attendance peaked in April immediately followed by a
marked drop and a pre-laying exodus in May. This
general pattern was true for one-bird-attendance and
the simultaneous attendance of two birds
(presumably a pair) at the nest-site. In 2006 and 2007
the pre-laying exodus (defined as no. days in a run
without the presence of the pair) at the individual
nest-sites started between 21 April and 4 May and
lasted for 21 to 32 days. In two cases when the length
of the exodus could be related to sex the male had a
shorter exodus than the female. A return from pre-
laying exodus did not always result in egg-laying (2
cases). In 2006 and 2007 copulations were observed
between 11 and 30 April and 20 April and 1 May,
respectively, though without any distinct peaks.
Besides, copulations occurred at all times of the day.
The total number of successful copulations (3-33),
time between first and last copulation (2-19 days), and
mean numbers (1.0-8.3) per day with copulations
varied considerable between the sites. No eggs were
laid in the two nests with the lowest mean number of
copulations.
Fróðskaparrit 57 bók 2009:89-108