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Part B - Technical instructions 
3.2 Migratory birds 
Table 3.2.1 : Radar survey. 
Baseline study 
Construction 
phase 
Operation phase 
Objectives 
Recording of bird movements 
(migration, foraging, flights 
between feeding and resting 
grounds etc.). 
Recording of 
impact due to 
construction 
(evasive beha 
viour, attraction 
etc.). 
Recording of impact due to 
operation (evasive behaviour, 
attraction etc.). 
Scope 
Survey frequency in the main migration periods 7 days/month (not in a single block). 
Main migration periods: March to May and mid-July to November. 
In total, at least 50 survey days are required. During these periods, at least 900 survey 
hours must be suitable for evaluation. 
A survey day comprises 24 hours. The surveys should cover full, uninterrupted 
24-hour cycles. The aim is to record bird migration and migration behaviour as evenly 
as possible in the course of a day (day- and night-time). 
Observation of flying birds’ reaction to the wind 
turbines (evasive behaviour, attraction etc.). In 
co-ordination with the BSH, the recording of birds 
in the rotor area should be recorded using state-of- 
the-art methods (optical systems (e. g. p. 62), radar 
detection). 
Timing 
At least two consecutive com 
plete seasonal cycles prior to the 
start of construction. 
Throughout the 
entire construc 
tion phase. 
At least three years, up to five 
years if required, after commissio 
ning. 
Method 
Radar surveys (after Hüppop et al. 2002) to be carried out for determining migration 
intensity and flight altitudes. 
Location: If a platform is available that is suitable with regards to location and equip 
ment (e. g. FINO, USPW), surveys should be carried out from the platform; otherwise, 
ship based surveys exclusively at fixed positions (e. g. anchoring buoy). A fixed posi 
tion is obligatory for cluster studies. The location for ship based surveys should be 
chosen relative to the wind farm in the direction from where most of the birds come to 
ensure optimal detection of the evasive movements of flying birds. 
Vertical radar: 
• Objective: Estimation of seasonal phenology of flight intensities. 
• Quantification of flight intensities at 100-m steps up to an altitude of 1,000 m, cor 
rected. During construction and operation phase, migration rates must be assessed 
especially in the rotor area of wind turbines. 
• Survey conditions: Depending on the ship's configuration, the surveys can be 
usually carried out in stronger winds of up to 7 Bft and at wave heights of up to 
2.5 m. Platform based surveys can be carried out at even higher wave heights. 
• Radar specifications: Vertical radar with an output of min. 25 kW, a vertical beam 
width of 20° to 25°, a horizontal beam width of 0.9° to 1.2° and a transmission 
frequency of about 9.4 GHz (x-band radar). The antenna's plane of rotation should 
preferably be aligned vertical to the assumed migratory direction. 
• Standard operating range: 1.5 km. 
• Comparability of results is essential in selecting equipment and making equipment 
settings. The filter for sea clutter (SEA) and rain (RAIN) should be set at 0. The GAIN 
filter should be determined individually for each radar device. Principally, the high 
est possible GAIN should be used, to avoid disturbance in the radar image. Identi 
cal radar device settings should be maintained throughout the entire assessment 
period.