Bird’s flight from Canada to Cuba via Bermuda tracked
The flight path of a great blue heron that stopped off in Bermuda during a 2,000 mile-plus migration from Canada to Cuba has been tracked by a team of US scientists.
The heron, named Harper, left her summer feeding ground in New Brunswick, Canada, on October 2.
She arrived in Bermuda 40 hours later and spent three days on the island before she headed south to Cuba on another 30-hour flight.
The bird was fitted with a solar panel GPS transmitter by scientists from the Heron Observation Network of Maine.
A post on the group’s website said: “She spent three days in Bermuda before flying another 30 hours to the Bahamas.
“She spent eight hours there before completing her journey’s final leg to Guajaca Uno.
“Her seven-day journey covered 2,130 miles, most of it over open ocean.”
Miguel Mejias of the Bermuda Audubon Society said that the migration habits of some birds were still not full understood.
He said: “While 21st century researchers have a much better understanding of the movements migratory birds take, as seen with Harper, the mechanics which birds use to do this is still not very well understood and heavily debated.
“Some have hypothesised that birds use celestial cues, using the sun’s angle and stars to orient themselves north to south during daytime and night-time travel, respectively.
“Another is that birds have sensory organs which use the earth's magnetic field to guide their movements. Landmarks, such as mountain ranges, rivers, are also thought to serve as important reference points to aid migratory birds to their destination.”
Mr Mejias added: “Even olfactory, or scent, cues are thought to be important, with some birds picking up specific odour signals emitted from their desired habitat.
“With the great blue heron, this might be the smell of fresh/brackish water. Studies have shown that birds have an incredible homing ability, with translocation experiments showing that birds released hundreds, sometimes thousands, of miles away from their breeding locality can readily return to said site, albeit after as many 12 days.”
Mr Mejias said that great blue herons could be found wading or standing along ponds, lakes, bays, harbours, vegetable gardens, and grassy fields.
He added: “Their numbers peak slightly in September and October, when the island receives migratory birds from the North American continent.
“During their peak abundance in the fall/winter, probably about a dozen GBHs reside on the island. Several factors influence the duration any given bird remains. Many species of migratory birds are site faithful, often returning to their favoured wintering site, year after year.
“So, Harper, who appears to favour spending her non-breeding period in Cuba, only used Bermuda as a refuelling station to fatten up again before finishing her journey to her intended destination, hence, her brief stay.
“In contrast, other individual great blue herons, upon visiting Bermuda for the first time, may opt to spend their nonbreeding periods here each year.”
Mr Mejias said: “Birds, like people, have preferences and different personalities which ultimately govern their decision making in where and how long to stay in a given place.
“Like a vehicle requiring a full tank of gas prior to a road trip, fat reserves are key to avian migration.
“This is especially true for birds that cannot swim or get completely wet taking transoceanic routes as crashing in the ocean for these species spells certain death.”