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

The spring migration season, and hence the spring radar data set, can be divided in three
periods roughly covering different main groups of migrants. The early period (March-April
10) is the peak migration period of Eiders, Common Scoters and some other early migrants;
the middle period (April 11-May 15) cover the migration of Barnacle Geese, most ducks and
other migrants; the late spring period (last half of May) is the main migration period of Brent
Gees and waders breeding in arctic Russia. Analysing these three periods separately yielded
the same overall pattern as described above. A lower proportion of the overall migration
volume passed over sector C with the wind farm in operation compared to the preconstruction
period (Fig. 43, 44, 45). The largest difference was found for the late spring
period where the proportion passing over sector C was 36 % lower post- compared to preconstruction
(Fig. 45). For the other periods the corresponding decreases in the proportion of
the overall migration volume were 23 % (mid-spring) and 15 % (early spring) (Fig. 43, 44).
% of all echoes (flocks)
45
40
35
30
25
20
15
10
5
0
Lillgrund
A B C
Sector
D E
63
Early migrants
2002
2005
2008
2009
2010
Fig. 43. Distribution of bird echoes (flocks) with north-easterly flight directions registered by
radar over southern Öresund in early spring (March-April 10) during spring 2002 and 2005
pre- (filled bars) and 2008, 2009 and 2010 post-construction (open bars) of the wind farm at
Lillgrund for the different 10 km sectors (A-E, see Fig 7 & 40)
Fördelningen av fågelekon (flockar) med nordostliga flygriktningar registrerade med radar
över södra Öresundsområdet under den tidiga delen (mars-10 april) av vårarna 2002 och
2005 (före etablering av vindkraftparken på Lillgrund, grå staplar) samt 2008, 2009 och
2010 (efter att parken tagits i drift, vita staplar), fördelat på 10 km-sektorerna A-E (se Fig. 7
& 40)