Fróðskaparrit - 01.01.1983, Blaðsíða 81

84
THE AUTUMN MIGRATION AT AKRABERG,...
ANTHUS
20 25 30 5 10
ANTHUS
20 25 30 5 10 DATE
Fig. 6. Occurrence of Anthus-species.
ber of migrating birds of both species oc-
curred in southwesterly winds, and whereas
the Meadow Pipits migrated in smaller flocks,
the Rock Pipits migrated one by one mainly,
or perhaps two or three together, often in
connection with flocks of Meadow Pipits.
Also, the Rock Pipits showed greater hesi-
tancy concerning migration.
The occurrence of Wheatear was decreasing
during the period, and the daily number
fluctuated considerably, thus indicating a
rapid change of the resting birds (Figure 7).
The species is a breeding migrant in all the
North Atlantic area. As to typical individuals
it is possible to distinguish Greenland birds
Oe. oe. leuchorrhoa from Scandinavian (nomi-
nate subspecies), whereas the Faroese and
Icelandic birds constitute an intermediate
stage (Svensson 1975 and our own studies).
From the identification in the field it was
observed that from Sep. 20th. Scandinavian
types were in excess after a period of mainly
»Atlantic« types. During the following period
a mixture of subspecies occurred until Oct.
7th, from which date the few birds present
looked completely Scandinavian, apart from
a possible Greenland bird on Oct. lOth. Both
on Sep. 20th and Oct. 7th also other Scandi-
navian birds arrived, in accordance with the
wind conditions (table 2 and appenđix 2).
The occurrence of eastern Wheatears has
not even been mentioned as a possibility by
previous authors (Salomonsen 1963, William-
son 1970).
Also a passage of Icelandic Redwings T. i.
coburni took place. This subspecies can also
be distinguished in the field from Scandinavian
birds (nominate subspecies). The nominate
subspecies has been considered rare and/or
not very numerous so far (Salomonsen 1963),
but it occurred regularly during the last fort-
night and totalled a majority compared to
the Faroese/Icelandic subspecies which was
only observed with certainty from Oct. lst.