Garde Baptiste, Wilson Rory P, Fell Adam, Cole Nik, Tatayah Vikash, Holton Mark D, Rose Kayleigh A R, Metcalfe Richard S, Robotka Hermina, Wikelski Martin, Tremblay Fred, Whelan Shannon, Elliott Kyle H, Shepard Emily L C
Department of Biosciences Swansea University Swansea UK.
Biological and Environmental Sciences University of Stirling Stirling UK.
Methods Ecol Evol. 2022 Apr;13(4):813-825. doi: 10.1111/2041-210X.13804. Epub 2022 Feb 7.
Accelerometers in animal-attached tags are powerful tools in behavioural ecology, they can be used to determine behaviour and provide proxies for movement-based energy expenditure. Researchers are collecting and archiving data across systems, seasons and device types. However, using data repositories to draw ecological inference requires a good understanding of the error introduced according to sensor type and position on the study animal and protocols for error assessment and minimisation.Using laboratory trials, we examine the absolute accuracy of tri-axial accelerometers and determine how inaccuracies impact measurements of dynamic body acceleration (DBA), a proxy for energy expenditure, in human participants. We then examine how tag type and placement affect the acceleration signal in birds, using pigeons flying in a wind tunnel, with tags mounted simultaneously in two positions, and back- and tail-mounted tags deployed on wild kittiwakes . Finally, we present a case study where two generations of tag were deployed using different attachment procedures on red-tailed tropicbirds foraging in different seasons.Bench tests showed that individual acceleration axes required a two-level correction to eliminate measurement error. This resulted in DBA differences of up to 5% between calibrated and uncalibrated tags for humans walking at a range of speeds. Device position was associated with greater variation in DBA, with upper and lower back-mounted tags varying by 9% in pigeons, and tail- and back-mounted tags varying by 13% in kittiwakes. The tropicbird study highlighted the difficulties of attributing changes in signal amplitude to a single factor when confounding influences tend to covary, as DBA varied by 25% between seasons.Accelerometer accuracy, tag placement and attachment critically affect the signal amplitude and thereby the ability of the system to detect biologically meaningful phenomena. We propose a simple method to calibrate accelerometers that can be executed under field conditions. This should be used prior to deployments and archived with resulting data. We also suggest a way that researchers can assess accuracy in previously collected data, and caution that variable tag placement and attachment can increase sensor noise and even generate trends that have no biological meaning.
安装在动物身上的标签中的加速度计是行为生态学中的强大工具，可用于确定行为并为基于运动的能量消耗提供替代指标。研究人员正在跨系统、季节和设备类型收集和存档数据。然而，使用数据存储库进行生态推断需要很好地理解根据传感器类型、在研究动物身上的位置以及误差评估和最小化协议所引入的误差。通过实验室试验，我们检查了三轴加速度计的绝对精度，并确定了误差如何影响人类参与者中动态身体加速度（DBA，能量消耗的替代指标）的测量。然后，我们使用在风洞中飞行的鸽子，在两个位置同时安装标签，并在野生三趾鸥上部署背部和尾部安装的标签，研究标签类型和放置如何影响鸟类的加速度信号。最后，我们展示了一个案例研究，在不同季节觅食的红尾热带鸟上，两代标签采用不同的附着程序进行部署。基准测试表明，各个加速度轴需要进行两级校正以消除测量误差。这导致在一系列速度下行走的人类中，校准和未校准标签之间的DBA差异高达5%。设备位置与DBA的更大变化相关，鸽子背部上下安装的标签变化9%，三趾鸥尾部和背部安装的标签变化13%。热带鸟研究突出了在混杂影响往往相互协变时，将信号幅度变化归因于单一因素的困难，因为不同季节之间DBA变化了25%。加速度计精度、标签放置和附着严重影响信号幅度，从而影响系统检测生物学上有意义现象的能力。我们提出了一种可以在野外条件下执行的校准加速度计的简单方法。这应该在部署前使用并与所得数据一起存档。我们还建议研究人员评估先前收集数据准确性的方法，并提醒可变的标签放置和附着会增加传感器噪声，甚至产生没有生物学意义的趋势。
