Brood surveys are used to estimate productivity in ducks, but road-side transects, aerial surveys, and double-observer ground surveys have likely underestimated productivity. Duck broods are elusive and prefer wetlands with emergent vegetation where they hide at signs of disturbance, making it difficult to get accurate brood counts. Estimates of brood detection probabilities are typically below 50% and variable, which makes biological inferences about abundance tenuous. We conducted a study to evaluate the efficacy of using an unmanned aerial vehicle (UAV) equipped with a thermal imaging camera to survey duck broods in 2 study areas. In Manitoba we located 669 broods with the UAV, compared to 344 detected by double-observer ground surveys. In Minnesota we detected 225 ducks broods with the UAV, whereas only 105 duck broods were detected by ground observers. Using a Huggins closed-capture model in program MARK we estimated an average detection probability across both sites of 0.55 (SE = 0.02) with the UAV compared to 0.24 (SE = 0.02) for the ground crews. Although the UAV detected twice as many broods as the ground surveys, detection probability with the UAV was impacted by temperature, humidity, vegetation density, and the criteria we used to determine whether a brood could be classified as resighted. Nevertheless, using a UAV equipped with a thermal imaging camera effectively doubled the number of broods detected compared to traditional methods, and surveys were completed 3 times faster. With advancing drone and camera technology we believe UAV brood counts will become increasingly accurate and provide reliable measures of local duck productivity. © 2021 The Wildlife Society.

中文翻译：

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无人机和热像仪在鸭窝调查中的应用

育雏调查用于估计鸭子的生产力，但路边断面、航空调查和双观察者地面调查可能低估了生产力。鸭子育雏难以捉摸，它们更喜欢有新植被的湿地，它们躲在有干扰迹象的地方，因此很难获得准确的育雏数量。育雏检测概率的估计值通常低于 50% 并且是可变的，这使得关于丰度的生物学推断变得脆弱。我们进行了一项研究，以评估使用配备热成像相机的无人机 (UAV) 在 2 个研究区域调查鸭子的效果。在曼尼托巴，我们用无人机定位了 669 个巢穴，而双观测器地面调查发现了 344 个。在明尼苏达州，我们用无人机探测到了 225 只鸭子，而地面观察员仅检测到 105 只鸭子。在程序 MARK 中使用 Huggins 封闭捕获模型，我们估计两个站点的平均检测概率为 0.55 (SE = 0.02)，而地勤人员则为 0.24 (SE = 0.02)。尽管无人机探测到的巢穴数量是地面调查的两倍，但无人机的探测概率受到温度、湿度、植被密度以及我们用来确定巢穴是否可以归类为重新观察的标准的影响。尽管如此，与传统方法相比，使用配备热成像相机的无人机有效地使检测到的育雏数量增加了一倍，调查的完成速度提高了 3 倍。随着无人机和相机技术的进步，我们相信无人机的育雏计数将变得越来越准确，并为当地鸭子的生产力提供可靠的衡量标准。© 2021 野生动物协会。