Thinking small: next-generation sensor networks close the size gap in vertebrate biologging

Abstract

<jats:title>Abstract</jats:title><jats:p>Recent advances in animal tracking technology have ushered in a new era in biologging. However, the considerable size of many sophisticated biologging devices restricts their application to larger animals, while old-fashioned techniques often still represent the state-of-the-art for studying small vertebrates. In industrial applications, low-power wireless sensor networks fulfill requirements similar to those needed to monitor animal behavior at high resolution and at low tag weight. We developed a wireless biologging network (WBN), which enables simultaneous direct proximity sensing, high-resolution tracking, and long-range remote data download at tag weights of one to two grams. Deployments to study wild bats created social networks and flight trajectories of unprecedented quality. Our developments highlight the vast capabilities of WBNs and their potential to close an important gap in biologging: fully automated tracking and proximity sensing of small animals, even in closed habitats, at high spatial and temporal resolution.</jats:p>

Vampire Bats that Cooperate in the Lab Maintain Their Social Networks in the Wild

“…After measuring dyadic rates of social grooming and food sharing over a period of 22 months in captivity, we then released 23 of the previously captive vampire bats (test group) back into their hollow tree and tracked their social associations in the field using custom-built ''next-generation'' proximity sensors [23][24][25]. As a control group, we also placed the same sensors on 27 additional wild female vampire bats from the same tree.…”

“…The proximity sensors used in this study were developed as a part of the BATS tracking system. The technological aspects of the system and its application are described in depth elsewhere [23][24][25]. The 1.8 g proximity sensor includes a 3D-printed plastic housing, a System-on-Chip for communication control and on-board data processing, a transceiver enabling communication with other proximity sensors or base stations in the sub-GHz band (903MHz), and a wake-up-receiver that activates full-system functionality from an energy-saving low-power mode.…”

An implantable neurophysiology platform: Broadening research capabilities in free-living and non-traditional animals

“…Breakthroughs in component miniaturization, computational capacity, and lowpower optimization have all contributed to the modern form factor and capability of biologgers and similar animal-borne telemetry systems (Wilmers et al, 2015;Harcourt et al, 2019;Whitford and Klimley, 2019). For example, spatially resolute wireless tracking systems have been used to investigate social complexity in bats (Ripperger et al, 2016(Ripperger et al, , 2019, understand nesting in starlings (Kirkpatrick et al, 2021), and pave the way for characterizing complex pair-bonding relationships. Small GPS loggers have utilized novel satellite networks to research migratory patterns of birds (Jetz et al, 2022) and were key to identifying the single longest migration on record in a gray whale (Mate et al, 2015).…”

ProxLogs: Miniaturised proximity loggers for monitoring association behaviour in small mammals

“…Our system is similar to previously described systems in some cases but also has some differences that we feel make it a valuable tool for answering specific questions. However, it should be noted that this system as is currently designed, will not provide the same long range spatial resolution as the BATS approach [26,27,24,33], and indeed has not been designed to. Rather, our system concentrates on short range associations and spatial…”