Bat 1: Estimate of bat populations at the southern North Sea : Supporting note to ZDV report no. 2016.031 Migration bats at the southern North Sea

To close the knowledge gap described above, or better said in order to make a start to overcome this crucial lack of insight into (sub)population sizes, RWS commissioned the Bats_1 study as part of the Wind op Zee Ecological Programma (Wozep; in English: Wind at Sea Ecological Programme), a multi-annual research programme initiated in view of the realisation of new offshore wind farms under the SER agreement (2013). Aim of the Bat_1 desk study is to estimate the extent to which (sub)populations of Nathusius’ Pipistrelle and possibly other relevant bat species, expressed in terms of numbers of individuals, use migration routes across the southern North Sea (SNS)1. This information is of great importance to be able to make better estimates of what the Potential Biological Removal (PBR) values are of Nathusius’ Pipistrelle and possibly other bat species, knowing that these values depend on the size of the (sub)populations to be considered.