UDTR Global Rights of Nature Radar

Directional variation and method-specific detection patterns in offshore bat migration: implications for wind farm mitigation

Identification

Public canonical key

radar:r-da7e61c94030bc968a21d140e4cebb27

Authors

Sander Lagerveld · Pepijn de Vries · Рахимбердиев Эльдар Нурланович · Jane Harris · Bart Noort · Steve C. V. Geelhoed · Frank van Langevelde · Fiona Mathews · Martin J.M. Poot · Julia Karagicheva

Reported year

2026

Reported language

en

Source type

preprint

First detected

2026-11-14T02:30:08.088326+00:00

Last metadata observation

2026-11-14T02:30:08.088326+00:00

Last HTTP verification

Not checked

Institutions reported by the source

Wageningen University & Research · University of Amsterdam · University of Sussex

Reported affiliation countries

GB · NL

Documentary abstract — original language

Abstract Curtailment of wind farms effectively reduces collision mortality in bats. Implementing this measure in offshore wind farms requires knowledge on the spatiotemporal occurrence and environmental predictors of migration over sea. In bats, such information can be obtained through acoustic monitoring and individual tracking. However, these techniques provide seemingly contradictory insights into migration patterns. We used a Bayesian capture–recapture state-space model to investigate how environmental predictors influence spring departure decisions of Nathusius’ pipistrelle Pipistrellus nathusii migrating over the North Sea. The model was applied to both acoustic and tracking data, enabling comparable analyses across methods and incorporating uncertainty in migration dates of tracked bats. Additionally, we examined nightly offshore bat occurrence to further explore differences in movement patterns detected by the two techniques. Wind conditions at 200 m above sea level were identified as key driver of Nathusius’ pipistrelle spring migration. In May–June, most bats migrated from the United Kingdom under westerly and northwesterly tailwinds. Tracked individuals flew in stronger supportive winds than acoustically recorded bats, which were also detected under crosswinds and headwinds. In March–April, acoustic detections occurred mainly during strong southerly winds, suggesting that early-season migrants largely consisted of individuals migrating over the European mainland and drifted northwards onto the North Sea by strong crosswinds. Acoustic detectors primarily recorded bats that landed on offshore platforms, likely because they were unable to cross the North Sea in a single flight due to less favorable wind conditions, or because they departed from more inland locations. In contrast, tracking data mainly represented bats that successfully crossed the North Sea in a non-stop flight under moderate supportive tailwinds. Synthesis and applications : Combining observation techniques improves our understanding of bat migration patterns. Additionally, acoustic monitoring can capture migration from different geographic origins. Current mitigation measures for offshore wind farms at the North Sea rely solely on acoustic data, likely overlooking the part of the population that crosses over sea with optimal wind support. Acoustic and tracking data are therefore complementary rather than contradictory, and both methods should be used together when developing mitigation measures.

Identifiers

OPENALEX

https://openalex.org/W7128389347

DOI

10.64898/2026.02.06.704313

Documentary context

Documentary family

preprint

Source-reported types

preprint

Entity mentions are not evidence of legal recognition. Jurisdiction studied is separate from author affiliation country.

Sources

OpenAlex · Record 1

• Document · https://doi.org/10.64898/2026.02.06.704313

Documentary status

Relevance pending

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