Automated monitoring of the occurrence and flight behaviours of White-throated Needletails Hirundapus caudacutus caudacutus at an operational wind farm in Tasmania

Abstract

The White-throated Needletail Hirundapus caudacutus caudacutus is listed as Vulnerable under the Australian Environment Protection and Biodiversity Conservation Act 1999, and interaction with onshore wind farms has been suggested as a threatening process for this taxon in Australia. Despite these concerns, there is an absence of data to assess the actual levels of risk and to design appropriate mitigation measures. We present a proof of concept for the use of the IdentiFlight System to automate the collection of data on occurrence and flight attributes of White-throated Needletails from an operational wind farm in Tasmania. Despite having not been recorded in pre-construction bird surveys using human surveyors, the automated detection system recorded 2982 tracks of White-throated Needletails passing through the site in the period 2020–2025, with 86% of the records occurring in February and March. Birds were recorded on a total of 377 days; there were single records on 144 (38%) days and ≥5 records on 105 (28%) days. When multiple records were recorded on the same day, the median timebetween the first and last detection was 4 minutes. There was a strong diurnal pattern, with peaks in occurrence 3–4 hours after dawn and 3–4 hours before dusk. Of the 2982 birds recorded, 53% had at least one height recorded within the rotor-swept area. These results clearly demonstrate the potential to utilise data collected by the IdentiFlight System to gain new insights into the interactions of White-throated Needletails with wind farms that can be used to inform risk assessments and mitigation approaches for this and other under-studied avifauna species.