Improved ecological insights commission new conservation targets for a crepuscular bird species

Abstract

Knowledge on species' ecological requirements is the key to an effective evidencebased conservation. An adaptive approach can refine management recommendations following the outcomes of previous actions or as improved scientific knowledge about a species' ecology becomes available. Following severe population declines the majority of the Swiss European Nightjar (Caprimulgus europaeus) population is now restricted to a small core area in the canton of Valais, despite the local application of evidence-based restoration measures to the breeding habitats. The habitat use of this crepuscular bird species is presumed to be restricted to semiopen oak-pine scrublands and rocky steppe. By deploying miniature GPS loggers we assessed the spatial and habitat selection of 42 individuals (25 individuals in 2018 and 30 individuals in 2019; comprising 13 redeployments between years) in five study sites in the canton Valais. We highlight the importance of using finescaled movement data to obtain insight into complex multi-scale habitat requirements of a species. Nightjars used multiple habitats, indicating the importance of complementary resources to breed (e.g. open forest and shrub) and to forage (e.g. semi-extensive grasslands and vineyards). The connectivity between these resources was influenced by habitat configuration and composition. Given these new insights for future conservation strategies, our results also suggest that national-level land use changes, mainly due to agricultural intensification processes, have contributed to the long-term population declines in Switzerland. We therefore consider our result in the context of knowledge gaps for species that exploit complementary habitats and the potential shortcomings for conservation planning on discrete species showing complex ecological requirements.

Quantifying song behavior in a free‐living, light‐weight, mobile bird using accelerometers

“…During the 2019 breeding season, we collected acceleration data in various sites in Belgium and Switzerland. All sites were well known from previous studies (Evens, Beenaerts, Neyens, et al, 2018; Evens et al, 2020). Behavioral classification using accelerometer data was also based on the data collected in these two countries.…”

“…Instead, we combined GPS data and field observations, an already widely used approach for behavioral classification and validation of these classifications in free‐living birds (Nathan et al, 2012; Patterson, Gilchrist, et al, 2019). We investigated GPS tracking data of well‐known individuals (Evens, Beenaerts, Neyens, et al, 2018; Evens et al, 2020) and we used field observations, sound recordings, and thermal videos (Pulsar Helion XQ38F Thermal Imaging Scope) to identify unique events of the target behaviors which could then be linked to acceleration measurements (Table 1; for a description of other target behavior, see Appendix ). In case of song behavior, we focused on identifying “churring” events.…”

Early successional habitats created through plantation harvesting benefit the Gray Nightjar (Caprimulgus jotaka): An 8-year survey in central Hokkaido, northern Japan

“…Second, nocturnal flying vertebrates may be physiologically sensitive to temperature; for example, the Red-necked Nightjar prefers warm roads on cold nights (Camacho 2013;De Felipe et al 2019). Although nightjar occupancy may also be influenced by other environmental factors correlated to elevation, such as young forest cover at larger scales (Kawamura et al 2016), pastures, or farmlands (Evens et al 2021), cool areas tend to restrict the distributions of Caprimulgidae species, which evolved in the tropics and share similar morphology and foraging ecology (Cleere and Nurney 1998).…”