On the Wings of Innovation

Animal migrations often involve awe-inspiring journeys that span across the globe, demonstrating the remarkable adaptability and instincts of countless species. These migratory patterns are essential for the survival of many animals, serving various purposes such as finding food, breeding grounds, or suitable climates. It is also important that we understand these migratory patterns, as this knowledge can be a key to preserving the delicate balance of ecosystems.

By observing the movements of species over time, scientists can assess the impact of environmental changes, such as habitat destruction, on wildlife populations. For example, shifts in migration patterns may indicate alterations in resource availability or the suitability of habitats. By identifying these changes early on, conservation efforts can be targeted to mitigate negative effects and preserve biodiversity. Furthermore, studying animal migrations provides valuable insights into animal behavior, physiology, and ecology.

Keeping watch over migratory patterns is not exactly simple, however, as many animals travel thousands of miles to reach their destination. But advances in sensing, processing, and communications technologies in recent years have made the job more practical. As these systems have simultaneously gotten more powerful, energy-efficient, and smaller, they have become more suitable for use in wearable devices that can transparently track the movements of an animal.

Even still, to supply enough battery power and radios with sufficient range, the devices are big enough that they are only suitable for use with larger animals. Unfortunately, this leaves tracking creatures like the monarch butterfly out of the question, which is a shame because there is a lot to learn from a tiny insect that seemingly bumbles its way through a journey of up to 2,500 miles, only to consistently reach a very specific destination. But with a novel tracking system called mSAIL that was developed by a team at the University of Pittsburgh and the University of Michigan, even butterflies can now be monitored across the globe.

The tracking device is housed in an 8 × 8 × 2.6 millimeter package that weighs in at just 62 milligrams. Within this diminutive casing, the researchers managed to squeeze in a custom battery, a solar cell for recharging, an ultra-low-power processor, temperature and light sensors, and a crystal-free radio. As the sensors collect data, the processor is used to compress it such that it can all fit within the 16 kilobytes of memory that is available onboard. Data can be collected from the device by listening for a broadcast from its radio.

An interesting method was used to infer the location of the animal wearing the tracker. Traditional methods, like GPS, require too much energy for use in such a tiny system. The team instead collected light and temperature measurements, then pairing those readings with the date, they trained a machine learning model that can predict the approximate location where the measurements were captured. While this approach does not have the accuracy of GPS, it was shown to achieve an error of less than 0.6 degrees latitude and 1.7 degrees longitude.

Looking to the future, the researchers see two directions in which to expand their work. On the one hand, the next obvious step is to optimize their fabrication techniques such that it will be possible to equip thousands of tiny animals with tracking systems. They also see an opportunity for their technology to be leveraged in bio-hybrid systems, in which the incredible sensing capabilities of biological organisms can be fed into their electronic devices for further analysis. This could be a great data source for artificial intelligence algorithms, in particular.