(Table 1) Comparison of dive duration and speed of Adélie penguins (Pygoscelis adeliae) equipped with internal and external devices@en

Bio-logging studies suffer from the lack of real controls. However, it is still possible to compare indirect parameters between control and equipped animals to assess the level of global disturbance due to instrumentation. In addition, it is also possible to compare the behaviour of free-ranging animals between individuals equipped with different techniques or instruments to determine the less deleterious approach. We instrumented Adelie Penguins (Pygoscelis adeliae) with internal or external time-depth recorders and monitored them in parallel with a control group during the first foraging trip following instrumentation. Foraging trip duration was significantly longer in the internally-equipped group. This difference was due to a larger number of dives, reflecting a lower foraging ability or a higher food demand, and longer periods of recovery at the surface. These longer recovery periods were likely to be due to a reduced efficiency to ventilate at the surface, probably because the implanted devices pressurised adjacent organs such as air sacs. Moreover, descent and ascent rates were slightly lower in externally-equipped penguins, presumably because external instrumentation increased the bird drag. Looking at our results, implantation appears more disadvantageous - at least for short-term deployment - than external equipment in Adelie Penguins, while this method has been described to induce no negative effects in long-term studies. This underlines the need to control for potential effects due to methodological aspects in any study using data loggers in free-ranging animals, to minimise disturbance and collect reliable data.生物记录（bio-logging）研究常面临缺乏真实对照组的难题。不过，仍可通过对比对照组与佩戴实验装置个体的间接参数，评估安装设备所引发的整体干扰程度。此外，还可对比采用不同技术或设备的自由活动野生动物的行为表现，以筛选出危害更低的实验方案。本研究为阿德利企鹅（Pygoscelis adeliae）安装了内置或外置式时间深度记录仪（time-depth recorders），并在设备安装后的首次觅食旅程中，同步对其与对照组个体开展监测。佩戴内置设备的实验组，其觅食旅程时长显著更长。该时长差异源于其潜水次数更多——这既反映出觅食能力下降，也可能意味着食物需求提升——同时其水面恢复时长也有所延长。这类更长的水面恢复时长，大概率源于企鹅在水面的换气效率降低，推测原因是植入式设备对气囊等邻近器官造成了压迫。此外，佩戴外置设备的企鹅，其下潜与上升速率略低，推测原因是外置设备增加了其游泳流体阻力。综合本研究结果来看，在阿德利企鹅中，植入式设备至少在短期部署场景下，比外置设备带来的负面影响更大；而此前已有研究表明，该植入方法在长期研究中并未产生负面效应。这凸显出：在任何针对自由活动野生动物使用数据记录仪（data loggers）的研究中，都需要控制实验方法层面潜在的干扰效应，以最大限度降低对动物的干扰并获取可靠的实验数据。