(Dec. 19, 2014) The snowy owl “Delaware,” newly outfitted with a Teflon-ribbon backpack containing a GPS transmitter, solar cell and rechargeable battery, has been transmitting location data since she was released Dec. 11 at Assateague after recovering from a serious injury.
The owl underwent surgery to fuse bones in her wingtip, a novel treatment for an injury that could have led to a lifetime of captivity according to DNR veterinarians.
With rest and rehabilitation, she grew healthy enough for release, and may be transmitting data that would more than pay for the investment of treating her.
The transmitter will convey latitude and longitude, much like any GPS would, but will also register altitude — a measurement ornithologists don’t have much gathered hard data.
“The elevation,” said Dave Brinker, ecologist with the Department of Natural Resources, “isn’t as accurate as location but it’s not unusable.”
Brinker detailed an example of the margin of error by describing a scenario where a person holding a transmitter similar to the owl’s and standing in the surf at Assateague would register a meter or two above or below sea level, not 100 or 200 meters. So, the measurements aren’t crystal clear but, as Brinker said, scientists have no good data on how high these birds will fly when migrating.
The problem is power. A battery that would last a few years and constantly update location data would be too heavy for a snowy owl to fly, Brinker said. The solution is to include a lighter rechargeable battery and a solar cell to replenish power. When the transmitter detects cellular service, it burps out as much data as it can before power fails.
Owls are perhaps uniquely unqualified for this sort of measure for two reasons, Brinker said. For one, they’re owls and are most active at night. For another, during the day, snowy owls prefer to face the sun, Brinker said. The solar cell of the transmitter is located in the center of Delaware’s back.
These problems are really just academic until the owl starts moving around a bit, but in Ocean City the data could be useful in industry — particularly in wind turbines.
“Snowy owls don’t have much of a fear of water,” Brinker said, noting the owls will prey on fowl such gulls and sea ducks.
Delaware herself had acquired a taste for dolphin, as she was apparently covered in it one’s remnants when she was first banded for a different kind of tracking, earning her the nickname “dolphin eater.”
As a result, when the owls forage for food, knowing their elevation as well as their location could prove useful for wind turbine placement. Critics frequently accuse wind turbines of having adverse effects on migrating wildfowl populations.
“These birds will eventually cross the Appalachian mountains. If they’re 200 feet above the ridgeline that puts them within the path of a rotor sweep. If they’re 1,000 feet above the ridgeline we can see they’re safe,” Brinker said.
Snowy owls are currently undergoing a little-understood migratory anomaly called an “irruption,” where they move much farther south than they normally would. Last year was one of the biggest irruptions in a century, according to Project SNOWstorm, a group formed to study this particular event.
With wind turbines coming to the Ocean City coast sooner rather than later, this data could go a long way in minimizing potential environmental impacts of wind farms.