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

Radar studies of bird migration
Spring - north-easterly directed migration
General
Most birds migrating over southern Öresund in spring approach from southwest and pass the
area in directions towards northeast. (Fig. 40). Several million of migratory birds are passing
each season and the movements include most groups of birds. Birds normally migrating at
lower altitude through the area and hence risking to get into contact with the wind farm
include Barnacle Geese, Brent Geese and other waterfowl species. Most migratory
movements of other species and groups probably pass at altitudes well above the turbines in
most cases, but can of course also pass at lower altitudes, especially in head wind conditions.
The annual total number of radar echoes (flocks) registered passing the 50 km transect A-E
during analysed days in spring 2002, 2005, 2008, 2009 and 2010 varied between 9000 and
18 000 (Table A11 in the appendix) probably corresponding to in the order of between 0.5
and 1 million individual birds if we assume an average flock size of 50 individuals per flock.
Fig. 40. General migration patterns over the southern Öresund in spring according to radar
data from 2002, 2005, 2008, 2009 and 2010 (yellow arrows show generalised migration
directions). Lillgrund with the wind farm is shown by the red square. The transect (A-E)
along which radar echoes (bird flocks) were counted is also shown.
Generellt flyttningsmönster hos majoriteten av alla fåglar över södra Öresund enligt
radarstudier vårarna 2002, 2005, 2008, 2009 och 2010 (gula pilar anger generella
flygriktningar). Lillgrund är markerat med en röd kvadrat. Transekten (A-E) som användes
vid eko (fågelflock) räkning visas också.
60
A
B
C
D
E