Visitors Heading North
Four of the five snowy owls in Pennsylvania that were tagged and outfitted with cellular transmitters this winter, including two in northwest Pennsylvania, have flown hundreds of miles north, according to Scott Weidensaul.
Weidensaul, an author and a naturalist, is involved with Project Snowstorm, which is tracking 22 of the 23 owls tagged this winter.
The project’s website explains that “Snowy owls normally live their lives in the endless summer sunshine and perpetual winter darkness of the high Arctic. But every once in a while, for reasons that are not fully understood, snowy owls come flooding down from the north in a phenomenon known as an irruption.”
Most of the owls were named after the location where they were captured, banded and released.
“Erie,” an owl tagged near Presque Isle, has flown the farthest north. He spent most of the winter on the ice on Lake Erie, presumably feeding on waterfowl near open waters around wind-driven ice. After flying to Buffalo and the northern shore of the lake, he is now clearly migrating, and was last reported northeast of Flint Michigan.
The cellular transmitters are outfitted with GPS and altimeters, and can record data in three dimensions, latitude, longitude and altitude up to once every 30 seconds, although since they are re-charged by solar panels, only one owl’s transmitter does so that often. The rest record data once every three minutes, Weidensaul, co-director of the project, said in an interview on Monday.
“It has been a steep learning curve for all of us,” he said. “There has been a lot of ground-breaking research, and we discovered that most of what we knew was wrong.”
“One of the myths that was busted pretty thoroughly was that they were doomed birds, starving and dying. We discovered that most are young birds that are incredibly healthy, with rolls of fat under their skin,” he said. “Fat is migratory fuel.”
He explained that snowy owls are general predators, feeding on whatever is available from rodents to ducks, and even carrion. Some owls were feeding on dead dolphin carcasses in Delaware this year.
“They are very agile and fast, capable of taking ducks mid-air,” he added, “even black ducks, which are very fast.
One of the most surprising things they discovered, however is how individualistic the owls are. “Some are homebodies, staying within a half mile of where they were tagged. Others travelled hundreds of miles, like ‘Erie.’ I shouldn’t play favorites, but Erie is my favorite,” he said.
Unfortunately, some owls have a predilection for the open spaces, and he said that a “bunch were killed at Pennsylvania airports.” A banded owl named Philly was killed on Jan. 29 at the Philadelphia airport when he was struck by a cargo jet.
Weidensaul said some owls actually go north in the winter and hunt off the Arctic pack ice.
Another misconception in years past was the number of snowy owls, he said. It was thought that there were several hundred thousand based on counts at their breeding grounds, but satellite transmitters showed that owls used different breeding grounds at different years and could have been counted as different birds and number of times.
It is believed now that there are about 7,500 breeding pairs world-wide, he said.
Populations vary, and the owls’ breeding numbers are directly related to lemming populations.
He said there is a theory that a decrease in trapping Arctic foxes may increase the predations on lemmings, reducing the amount of food needed by snowy owls.
The transmitters do not cause the owls any problems with feeding, flying or breeding based on prior research with satellite transmitters. “They only weigh about two percent of the owl’s weight, and I am very confident that they shouldn’t have any long-term effects on the birds. They are placed on the owl’s backs at their center of gravity,” which is important for stable, easy flight.
He said the transmitters can store almost six years of data, and if the birds should return in another year or more, they will be able to download whatever data has been stored.
“If they stay in the Arctic for a winter or more, the transmitters will go into hibernation, but when the sun comes back in the spring, they will charge back-up with their solar panels,” he said.
“There is a very good chance we will collect data in the years to come,” he concluded.
Earlier this year, kindergarten through eighth grade students in Learning Enrichment Center in John Fedak’s class students raised $24,000 to fund Project Snowstorm.
Project Snowstorm credited the Pennsylvania Society for Ornithology with supplying Erie’s transmitter. Fedak is the president of the society.
To view maps of each owl, go to www.projectsnowstorm.org/maps/.