Birds in southern Öresund in relation to the wind farm at ... - Vattenfall

% of all echoes (flocks)
20
15
10
5
0
2002 2005 2008
Year
2009 2010
Fig. 50. The proportion of bird echoes (flocks) passing Lillgrund, 3x3 km covering the wind
farm area and its close surroundings, with southerly flight directions in spring during preconstruction
(2002 and 2005, filled bars) and post construction (2008, 2009 and 2010, open
bars).
Andelen fågelekon (flockar) som passerade Lillgrund, 3x3 km innehållande vindkraftparken
och dess närmaste omgivningar, under det sydriktade vårsträcket av sjöfåglar åren 2002 och
2005 (före Lillgrundsparken byggdes, grå staplar) och 2008, 2009 och 2010 (efter att parken
tagits i bruk, vita staplar).
Autumn
General
The autumn bird migration over southern Öresund passes along a main axis from Northeast
towards southwest (Fig. 51). All sorts of birds are involved in the migratory movements in
autumn and it is harder to pin-point groups that are more likely to travel at low altitude
through the area, than it is in spring. Generally speaking, low-altitude migration is more
prevalent in head wind conditions. Depending on general weather conditions and especially
wind direction and strength, there are marked differences between different days in where the
corridor passes during that specific day. A general concentration effect to the Falsterbo
peninsula in the far southwest is usually apparent, as many land birds hesitate to the passage
of open water and tries to fly over land for as long as possible. The concentration to Falsterbo
is stronger in winds from the western sector and less pronounced in winds from north and
east.
The overall migration volume in autumn is of course higher than in spring, as all the offspring
of the breeding season are migrating at this time of the year in addition to all the adult birds.
This means that many millions of individual birds are passing over the southern Öresund area
in autumn. Annual totals of registered radar echoes (bird flocks) during analysed days in
autumn 2001, 2008 and 2009 varied between just under 9000 to 15 000 (Table A13 in
appendix). This probably corresponds to somewhere between 450 000 and 750 000 individual
70