40 
Part B - Technical instructions 
5 Bats 
Table 5.1: Survey of bat migration activity in the offshore area of the Baltic Sea. 
Baseline study 
Objectives 
Survey of bat migration (species spectrum, event frequency, activity maxima etc.) for 
the evaluation of the importance of the assessment area as a migratory zone for bats 
in the offshore region of the Baltic Sea. 
Scope 
The surveys should be carried out parallel to the night-time flight call monitoring of 
migratory birds (see table 3.2.2) in windless nights (up to 3 Bft) (see process instruc 
tion, p. 70). 
Timing 
At least two consecutive complete seasonal cycles prior to the start of construction. 
Method 
Use of bat detectors for monitoring call activity (see process instruction, p. 70). 
Presenta 
tion of 
results 
The number of recorded call sequences constitutes the activity. The data is rendered 
as “activity density”. All bat observations are therefore to be evaluated as a relative 
measure (see process instruction, p. 70). 
The data evaluation must contain: 
• List of observed bat species. 
• Presentation of seasonal distribution of species-specific activity. 
• Presentation of call activity over the course of the day. 
• Blending of activity data with collected weather data.