Fróðskaparrit - 01.01.1983, Blaðsíða 77

80
THE AUTUMN MIGRATION AT AKRABERG,...
Table 2.
Days with wind conditions above Scandinavia and the
Baltic area favourable for wind assisted migration to
the Faroes.
Winds NE E and SE SE to S
Date Sep. 19th
- 20th Sep. 20th
- 23th
- 24th - 24th Sep. 24th
- 25 th - 25th - 25th
- 26th - 26th - 26th
Oct. 2nd
- 3rd
- 4th
Oct. 6th
- 7th
- 8th
- 9th
- lOth
Table 3.
An outline of the division of the observation time.
3 hours land observations only
25 - sea observations only
15 - combined land/sea observations
In all 43 - migration observations
+ 124 - resting observations
In all 167 hours spread over 25 days of observation.
During all observations a 20x60 telescope
and 10x40 binoculars were used.
The observations of sea bird were best done
just below the lighthouse, 40 m. above sea
level, with a good view towards the east and
the south and with shelter. Móannes (figure
3), however, was the best place in case of
high onshore winds form the SW and in case
of strong backlight on the afore-mentioned
place. Ideally both places ought to be manned
during observations of sea birds.
When sea birds and migrating land birds
were observed at the same time, the light-
house, itself, was the best place for observa-
tions.
Number and flight direction were recorded
for all sea birds, but as to the numerous
species, Fulmar Fulmarus glacialis and Kitti-
wake Rissa tridactyla, counts were carried
out once every hour during a period of 5
minutes.
The activity of migrating land birds was
most marked during the first hours after
sunrise — and, to a smaller extent, late in the
day, but all in all migration was modest.
Presumably, this reflects reality, but add to
this that, owing to the topography of Akra-
berg, birds might cross above the observer’s
range of vision and hearing.
The best wind conditions for recording the
migrating passerines were fresh or moderate
breezes about the SW. In these conditions
the birds obviously had to fly lower before
they tried to cross the sea (Sep. 18thwith200
Meadow and Rock Pipits Anthus pratensis
and +. spinoletta in one hour).
Other migration movements took place
when small birds came from the sea and
continued along the coast heading NW. Both
species partly migrating by day — such as
Sky Lark Alauda arvensis and Tree Pipit
Anthus trivialis — as well as species typi-
cally migrating by night — such as Willow
Warbler Phylloscopus trochilus and Pied
Flycatcher Ficedula hypoleuca — were ob-
served in this way. Migration by night was
only recorded once (Redwing) and no light-
house fall was found at all.
The resting birds were counted within fixed
areas. Partly the fields around the lighthouse
(fig. 2) at about 100 m. above sea level and
partly the areas near Sumba, including both
the coast, the gardens, and part of the fields.
The areas were walked through by the same
route each time in order to ensure the relative
value of the censuses. At the same time the