$7 Bluetooth Beacons, Linked to Apple's FindMy Network, Could Revolutionize Urban Animal Research

Researchers from the Australian National University, the University of Zurich, and the Max Planck Institute of Animal Behavior have come up with a low-cost way to track animals in urban environments — with a Bluetooth beacon that piggybacks on cellular phones.

"By piggybacking off the global network of personal mobile phones, we're using Bluetooth beacons as a gateway for tracking animals, and we've demonstrated its potential to study the movements, home ranges and social networks of urban living animals," explains lead author Damien Farine, associate professor of ecology at ANU, of the project. "“Until now animal tracking studies have faced technological limitations such as high costs or the need for tags to remain near detectors, and this new device overcomes these limitations."

The beacon developed by the team is based on an unspecified model in Nordic Semiconductor's nRF5 system-on-chip family, installed in a low-cost beacon weighing just 1.48g before the battery is added and able to be constructed into a robust animal-mountable device with 3D-printed housing for under $7. "Boards are usually built to take a standard CR2032 battery weighing 2.9g," the researchers add, "but can also be fitted with smaller, lighter batteries (albeit resulting in shorter battery life.)"

"The device works through mobile phones, so as people walk near the birds, they pick up the tag's signal, and their phones upload the data to the cloud," Farine explains, with the team using a software stack designed to piggyback on Apple's FindMy ecosystem using the open-source OpenHaystack firmware. "This all happens automatically with no information collected about the phones themselves, only the identity and location of the tag. Animals can have fascinating responses to urban habitats, and the ability to cheaply and reliably track them will help to unlock many secrets of our urban wildlife."

The team tested the beacons using a population of sulfur-crested cockatoos, a large parrot that has adapted to exploit human occupation, and one of smaller white-wing choughs. Although successful, the trials highlighted the potential for further improvements — including the installation of gateways to cover areas with a lack of FindMy-compatible smart devices, the need to reduce the size and weight of the trackers still further, and the potential for installing additional sensors like accelerometers to provide richer data.

"There’s a lot that we still have to learn about how animals adapt to and survive in urban habitats," Farine concludes, "but the tags we developed are cheap, lightweight, and have no download costs."

The team's work has been published in the journal Methods in Ecology and Evolution under open-access terms.