D1, a Decorah eagle hatched in 2011 and fitted with a satellite transmitter that same year, is again spending her summer in Polar Bear Provincial Park above the tree line on Canada's Hudson Bay.
This is the third year in a row she has left Decorah in the spring and traveled more than 1,000 miles to her unpeopled summer home in the sub-arctic wilderness.
As in years past, she likely will return to Decorah in the fall and spend the winter there.
“This will probably be her last long summer vacation,” said raptor expert Bob Anderson, who with eagle researcher Brett Mandernack fitted D-1 with a solar-powered satellite transmitter July 12, 2011, to learn what becomes of young northern eagles after they leave the nest.
D1 will reach sexual maturity next spring and likely will attract a mate and attempt a nest, probably somewhere near Decorah, said Anderson, director of the Raptor Resource Project, whose nest-cam website recorded its 300 millionth visitor earlier this year.
“She will be 4 years old next spring — the same age as her mother when she raised her first chicks,” he said.
When Anderson last saw D1 more than a month ago, her head was three-quarters white. By next spring she should be sporting the pure white head and tail fan of a mature bald eagle, he said.
In her first year, D-1 (for Decorah first satellite) took a four-month, 900-mile tour of Minnesota and Wisconsin before returning to Decorah on Dec. 28, 2011.
Her first trip to Hudson Bay in 2012 took a leisurely 39 days. Last year, she made the trip in 15 days, and this year it took her 17 days, leaving Decorah on May 27 and arriving June 12 at Hudson Bay.
“Her travels have been absolutely amazing. I couldn't imagine that an Iowa eagle would spend three summers near the arctic,” Anderson said.
Anderson said he hopes the solar-powered transmitter, soon to be entering its fourth year of operation, will keep working at least until D-1 reaches reproductive maturity and starts raising young of her own.
Polar Bear Provincial Park consists of more than 9,000 square miles of isolated tundra established to protect the fragile habitat of polar bears. Accessible only by air, it has no human inhabitants and few human visitors. It borders the southern shores of Hudson Bay and the western shores of James Bay.
Anderson said recent satellite readings have placed D1 more than 30 miles off shore on the bay's remaining ice. Anderson said his friend, renowned wildlife photographer Jim Brandenburg, whose portfolio includes many polar bear photos, speculates that D1 is feeding off the remnants of seals killed by polar bears.
“Three months from now she will start her return trip,” Anderson said. “You can almost set your clock by her.”