Michigan’s Mute Swan Research Leverages Emerging Technologies
By Randall Knapik
The presence of mute swans (Cygnus olor) in the Great Lakes region of North America serves as a visible reminder to our connected cultures, economies and world. In response to marked population expansion at the turn of the 21st century, management policies were adopted by the Michigan Department of Natural Resources (DNR) and Mississippi Flyway Council to reduce abundance of introduced mute swans to levels that minimize impacts to wetlands, native wildlife, and humans by the year 2030; however, it was unknown if mute swan nesting ecology, survival, and movement in the region was characteristic of their native range. A research collaboration between Michigan State University, the Michigan DNR, and the Wildlife Service’s section of the U.S. Department of Agriculture was formed in 2014 to better understand biological aspects of mute swans within Michigan with the expressed goal of using that information to guide future management strategies.
This research has leveraged technological advances to achieve project objectives with regard to clutch sizes, nest survival, and dispersal, but it has also used that technology to further knowledge of other aspects of mute swan biology which is irrespective of their introduced or native status. Nest fate was successfully monitored without the intrusion of routine nest checks through use of small temperature loggers (DS1921G-F5#; Maxim Integrated San Jose, CA, USA; Figure 1) placed below each clutch of eggs. Exact timing of nest hatch or failure was determined by comparing in-nest temperature to ambient conditions. Life stage-specific survival was remotely estimated through use of fine-scale telemetry locations, triaxial accelerometers, and onboard temperature loggers. Additionally, biological information that had long escaped direct measure, like flight speed and altitude, was quantified through emerging technologies. Flexible duty cycles of GPS-GSM transmitters (i.e., FlightMode; Cellular Tracking Technologies, Inc., Rio Grande, New Jersey, USA; Figure 2) now allowed for instantaneous adjustment of GPS fix rates after detection of flight using onboard accelerometers. Fix rates of 1 GPS location per 10 seconds, coupled with the recording of altitude, heading, and flight speed, have provided the first detailed look at mute swan flight to the researcher’s knowledge. Results of this nesting ecology, movement, and survival study, including estimates of flight speed and altitude, intend be published at the conclusion of the research 2019.
Figure 1. A small temperature-logging device (DS1921G-F5#; Maxim Integrated San Jose, CA, USA) was placed below this average-sized clutch of mute swan eggs (n = 7) in Michigan, USA, to identify timing of nest hatch or failure based off comparisons of nest temperature to ambient. Eggs were sequentially numbered with colored markers following laying order to help identify egg fate at nest hatch or failure.
Figure 2. A two-year-old mute swan in Michigan, USA, with neck collar-mounted GPS-GSM transmitter (Cellular Tracking Technologies, Inc., Rio Grande, New Jersey, USA) that recorded flight speed, altitude, heading, and position at 10 second intervals during flight bouts through flexible duty cycle technology.