Goldenberg Shifra Z, Cryan Paul M, Gorresen Paulo Marcos, Fingersh Lee Jay
Conservation Ecology Center Smithsonian Conservation Biology Institute Front Royal VA USA.
Institute for Conservation Research San Diego Zoo Global Escondido CA USA.
Ecol Evol. 2021 Mar 18;11(9):4843-4853. doi: 10.1002/ece3.7388. eCollection 2021 May.
Bat fatalities at wind energy facilities in North America are predominantly comprised of migratory, tree-dependent species, but it is unclear why these bats are at higher risk. Factors influencing bat susceptibility to wind turbines might be revealed by temporal patterns in their behaviors around these dynamic landscape structures. In northern temperate zones, fatalities occur mostly from July through October, but whether this reflects seasonally variable behaviors, passage of migrants, or some combination of factors remains unknown. In this study, we examined video imagery spanning one year in the state of Colorado in the United States, to characterize patterns of seasonal and nightly variability in bat behavior at a wind turbine. We detected bats on 177 of 306 nights representing approximately 3,800 hr of video and > 2,000 discrete bat events. We observed bats approaching the turbine throughout the night across all months during which bats were observed. Two distinct seasonal peaks of bat activity occurred in July and September, representing 30% and 42% increases in discrete bat events from the preceding months June and August, respectively. Bats exhibited behaviors around the turbine that increased in both diversity and duration in July and September. The peaks in bat events were reflected in chasing and turbine approach behaviors. Many of the bat events involved multiple approaches to the turbine, including when bats were displaced through the air by moving blades. The seasonal and nightly patterns we observed were consistent with the possibility that wind turbines invoke investigative behaviors in bats in late summer and autumn coincident with migration and that bats may return and fly close to wind turbines even after experiencing potentially disruptive stimuli like moving blades. Our results point to the need for a deeper understanding of the seasonality, drivers, and characteristics of bat movement across spatial scales.
北美风能设施中的蝙蝠死亡事件主要由依赖树木的迁徙物种构成，但尚不清楚为何这些蝙蝠面临更高风险。影响蝙蝠对风力涡轮机易感性的因素或许可通过它们在这些动态景观结构周围的行为时间模式得以揭示。在北温带地区，蝙蝠死亡大多发生在7月至10月，但这是反映季节性变化行为、候鸟迁徙，还是多种因素的某种组合，仍不明确。在本研究中，我们检查了美国科罗拉多州一年的视频图像，以描述风力涡轮机处蝙蝠行为的季节性和夜间变化模式。在306个夜晚中的177个夜晚检测到了蝙蝠，约3800小时的视频中出现了超过2000次离散的蝙蝠事件。在观察到蝙蝠的所有月份里，我们都观察到蝙蝠在整个夜间接近涡轮机。蝙蝠活动出现了两个明显的季节性高峰，分别在7月和9月，与前几个月6月和8月相比，离散蝙蝠事件分别增加了30%和42%。7月和9月，蝙蝠在涡轮机周围表现出的行为在多样性和持续时间上都有所增加。蝙蝠事件的高峰反映在追逐和接近涡轮机的行为上。许多蝙蝠事件涉及多次接近涡轮机，包括蝙蝠被转动的叶片在空中驱赶时。我们观察到的季节性和夜间模式与以下可能性相符：风力涡轮机在夏末和秋季引发蝙蝠的调查行为，这与迁徙同时发生，并且即使在经历了如转动叶片等潜在干扰刺激后，蝙蝠仍可能返回并靠近风力涡轮机飞行。我们的结果表明，有必要更深入地了解蝙蝠在不同空间尺度上的季节性、驱动因素和运动特征。
