Recent studies suggest that visual and acoustic anthropogenic disturbances can cause physiological stress in animals. Human-induced stress may be particularly problematic for birds as new technologies, such as drones, increasingly invade their low-altitude air space. Although professional and recreational drone usage is increasing rapidly, there is little information on how drones affect avian behavior and physiology. We examined the effects of drone activity on behavior and physiology in adult, box-nesting tree swallows (Tachycineta bicolor). Specifically, we monitored bird behavior during drone flights and in response to a control object and measured telomere lengths and corticosterone levels as indicators of longer-term physiological stress. We predicted that drone-exposed tree swallows would habituate behaviorally after multiple flights, but that telomeres would shorten more quickly and that baseline corticosterone levels would be altered. One significant and two strong, non-significant trends in behavioral assays indicated that adult swallows acted more aggressively towards drone presence compared to a control object, but were slower to approach the drone initially. Swallows were also more reluctant to use nest boxes during drone activity. Tree swallows habituated to drone presence as expected, although the rate of habituation often did not differ between drone-exposed and control groups. Contrary to our prediction, drone activity did not affect telomere length, corticosterone levels, body mass or fledging rates. Overall, our results indicate that a small number of short, targeted, drone flights do not impact tree swallow health or productivity differently than a non-invasive control object. Minor behavioral differences suggest that increasing the frequency of drone use could impact this species. We provide some of the first results addressing how drone activity alters behavioral, physiological and molecular responses to stress in songbirds. A better understanding of these impacts will allow ecologists to make more informed decisions on the use and regulation of new drone technologies.

中文翻译：

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短期接触无人飞行器不会改变繁殖树燕子的应激反应。

最近的研究表明，视觉和听觉的人为干扰会引起动物的生理压力。由于诸如无人机之类的新技术越来越多地侵入低空领空，因此人为引起的压力对于鸟类可能尤其成问题。尽管专业和休闲无人机的使用量正在迅速增加，但是关于无人机如何影响鸟类行为和生理的信息很少。我们检查了无人机活动对成年的箱形燕子（Tachycineta bicolor）成年行为和生理的影响。具体来说，我们监测了无人机飞行过程中鸟类的行为以及对控制对象的反应，并测量了端粒长度和皮质酮水平，作为长期生理压力的指标。我们预计，多次飞行后，暴露于无人机的树燕子会习惯性地行为，但是端粒缩短的更快，皮质酮的基线水平也会改变。行为分析中的一种显着趋势和两种强烈，非显着趋势表明，与对照对象相比，成年燕子对无人机的存在更具攻击性，但最初接近无人机的速度较慢。燕子在无人机活动期间也不愿使用巢箱。燕子习惯了无人机的出现，这与预期的一样，尽管习惯暴露的速度在暴露于无人机和对照组之间通常没有差异。与我们的预测相反，无人机的活动不会影响端粒长度，皮质酮水平，体重或出雏率。总体而言，我们的结果表明，少数简短，有针对性的，无人机飞行对树燕子健康或生产力的影响与非侵入性控制对象不同。轻微的行为差异表明，增加无人机使用频率可能会影响该物种。我们提供了一些关于无人机活动如何改变对鸣禽压力的行为，生理和分子反应的初步结果。对这些影响的更好理解将使生态学家可以就新无人机技术的使用和监管做出更明智的决定。