Birds pose significant challenges to track globally due to their small size and weight. Various techniques are used, including Passive Integrated Transponders (PIT Tags), radio (VHF) telemetry, light-level geolocation, stable isotope analyses, and satellite transponders. Individual marking (leg bands) is also a common practice and one of the first steps to understanding migratory connectivity.
Techniques and technologies to monitor migratory birds open new perspectives into the vast distances traversed throughout a birds life cycles and the habitats necessary for survival. Each technology, however, does have its own set of positives and negatives that must be considered prior to deployment. Leg bands, for instance, have been used for decades and come in a variety of sizes. Birds, however, must be recaptured in order for the data (the animal’s unique ID) on the tag to be recorded. Thus, no information is provided from the tag about the pathway it took to get from point A to point B. GPS telemetry tags offer improved resolution to these pathways, but are often too large for many species to carry.
Over the years, Smithsonian scientists have worked with a variety of manufacturers to increase the breadth of species that are able to be monitored using these emerging technologies. PinPoint GPS tags, for instance, weigh just 1g. This revolutionary tracker, designed by Lotek Wireless, is designed to fit songbirds that scientists have never been able to track due to previous weight restrictions from bulky tags. The comparable tag that was traditionally used weighs around 12g and could only be used on birds weighing at least 250g. By minimizing tag weight, scientists maximize research potential and are expanding the range of species that can be studied. Additional information on tracking technologies can be found on Smithsonian’s Migratory Connectivity Project website.