Data from: A new Magneto-Inductive tracking technique to uncover subterranean activity: what do animals do underground?

1. Despite the importance of the subterranean ecotope, knowledge of underground movement and behaviour has been extremely limited. Previous technologies have relied upon techniques with very low spatial or temporal resolution, such as VHF telemetry. Rather incongruously therefore, relatively simple underground activity regimes have often been assumed, with insufficient attention to the ecological importance of burrow use. 2. We test the capability of Magneto-Inductive (MI) tracking, recording underground movement within a European badger sett over a two week period in February. These data allowed us to: quantify subterranean movement; extrapolate the three-dimensional burrow architecture; simultaneously track multiple individuals; and establish the function of specific movement patterns; demonstrating the technique's utility. Contrasting data generated using MI tracking, against the resolution achievable with VHF tracking, we establish how sampling frequency can influence the percecption of movement. 3. Taking 20 locational fixes per minute, MI collars operated for one year before on-board batteries failed, resulting in an average five billion data points per collar deployment. Socio-ecologically we found that rather than foraging continuously throughout the night, badgers returned to the sett an average of 2.2 times, approximately every 3-4 hours. From burrow mapping, badgers tended to use peripheral chambers for ca. 45 minutes on these return visits,These outlying chambers were used less by day, when badgers selected deeper chambers, suggesting each chamber type fulfils a different function. This technology also exposed that badgers exhibited a far greater extent of underground movement than revealed by former technologies, which by comparison captured less than 0.5% of subterranean activity. Importantly, these high-resolution data showed that individuals left, returned to, and moved about the sett independently, with no tendency for synchronous subterranean activity. 4. In overview, magneto-inductive tracking proved relatively simple and cost effective to deploy, it provided very detailed and accurate subterranean fixes, and was robust enough for long-term field deployment. Furthermore, the capabilities of MI are highly transferable, enabling a better understanding of underground activity and the ecological importance of subterranean burrows for the conservation and management of a wide range of species.1. 尽管地下生境（subterranean ecotope）的重要性不言而喻，但目前学界对动物地下活动模式与行为的认知仍极为有限。过往的监测技术多依赖空间或时间分辨率极低的手段，例如甚高频遥测技术（VHF telemetry）。因此颇为矛盾的是，此前研究往往默认地下活动模式相对简单，却未充分重视洞穴利用行为的生态学意义。 2. 本研究于2月开展了为期两周的试验，利用磁感应（MI）追踪技术记录欧洲獾洞（European badger sett）内的地下活动轨迹。通过这批数据，我们得以完成多项分析：量化地下活动范围、推演三维洞穴结构、同时追踪多个个体，并明确特定活动模式的功能，从而验证了该技术的应用价值。通过将MI追踪所得数据与VHF遥测技术的分辨率上限进行对比，我们阐明了采样频率如何影响对动物运动的观测结果。 3. 该磁感应追踪项圈每分钟可采集20个定位点，内置电池可支持连续工作一年，单只项圈单次部署平均可产生50亿条数据。从社会生态学视角分析，獾并不会整夜持续觅食，而是平均每3-4小时返回獾洞一次，日均返回次数约为2.2次。通过洞穴测绘发现，獾在返回獾洞时，会在外围巢室停留约45分钟；而在日间活动中，獾则更少使用外围巢室，转而选择更深的巢室，这表明不同类型的巢室承担着不同功能。该技术还揭示，獾的地下活动范围远大于过往技术的观测结果——此前的技术仅能捕捉到不足0.5%的地下活动。尤为关键的是，这批高分辨率数据显示，每只獾都会独立离开、返回并在獾洞内活动，不存在同步开展地下活动的行为倾向。 4. 总体而言，磁感应追踪技术部署简便且成本效益可观，可提供高精度、高细节度的地下定位数据，且具备足够的耐用性以支持长期野外部署。此外，该技术的应用能力具有极强的可迁移性，有助于我们更深入地理解各类物种的地下活动模式，以及地下洞穴的生态学意义，从而为多物种的保护与管理工作提供支撑。