By Laura Koloski
It’s not often I get excited about technological advances. In a world of ever-evolving phones, tablets, and gadgets, I’m stuck fumbling with the buttons on my flip phone. But when new technologies improve our ability to study wildlife populations my interest skyrockets.
Studies on shorebird movement and migratory patterns have greatly benefitted from GPS, radio tracking, and geolocator technologies. For some species, however, the size and weight of monitoring units are major considerations that restrict the use of GPS to precisely track migration. Dunlin weigh in at less than 75 grams and the concern is that the added weight of a GPS transmitter would make it too difficult for a bird to complete its long distance migration. This is why we have relied on the lighter, more compact radio transmitters and geolocators for Dunlin monitoring.
Geolocators, which record ambient light levels to estimate location, have shown general migration pathways of Dunlin breeding in Churchill and wintering along the East Coast. Studies of Dunlin have employed radio transmitters to look at local movements and survival but not migration data, because signals can only be detected over small distances and receivers have not been set up for large scale studies.
Thanks to the efforts of scientists Chris Guglielmo, Ryan Norris, and Phil Taylor – who have recently developed a cost effective automated tracking system – an array of more than 100 radio receivers will be placed along bays and stopover sites likely used by arctic shorebirds on their southward migration routes. Around the Arctic, shorebirds will be fitted with radio transmitters as part of this study, to improve our understanding of migration patterns among some of the smaller species. My fieldwork researching Dunlin in Churchill, Manitoba, includes capturing birds on the nest and banding them. Attaching transmitters to a subset of individuals will be easily integrated into this process.
In Churchill, we will rely on transmitter signals to monitor individual Dunlin after families have left the nest and become highly mobile. This will provide information about Dunlin during the latter part of the breeding season, which is vital to my research on population characteristics on the breeding ground.
As the season draws to a close, an automated receiver will determine exactly when these birds leave the breeding grounds. Ideally, some of the individuals with transmitters will stop in for a few days or pass by one or more of the radio receivers during the fall migration. When the frequency is picked up we will gather specific data on the amount of time spent at a site as well as the time it took to travel there from Churchill.
While GPS technology provides more and better information than radio telemetry, it is still not a feasible option for studies of small shorebirds like the Dunlin. As we wait for the inevitable improvements to GPS tracking, radio telemetry systems such as this allow us to better understand shorebird migrations.
It may not garner the same fanfare as the release of the newest iPhone, but this new system can lead to new approaches to old problems, confirm that which was thought to be true, and sometimes reveal the unexpected.
Laura Koloski is currently studying the reproductive ecology of Dunlin in Churchill, Manitoba, as part of her M.Sc. studies at Trent University. Her project is part of the Arctic Shorebird Demographics Network, which is led by Manomet, the U.S. Fish and Wildlife Service and Kansas State University. Laura has also worked as a member of Manomet teams researching American Oystercatchers, shorebirds nesting on the North Slope, and landbird migration at Manomet headquarters.