The first whooping cranes banded with radio transmitters have completed a full migration cycle between Wood Buffalo National Park (WBNP) in Canada’s Northwest Territories and Aransas Wildlife Reserve in Texas, and the results are surprising.
One juvenile crane flew all the way to the park, a distance of 4,000 km from the Gulf of Mexico, before turning around to backtrack 500 km to Prince Albert, Saskatchewan.
Another juvenile, nicknamed RAY, actually ended up west of WBNP, near Fort Providence.
And the total migration time ranged from 14 days for an inspired group of adults, to 69 days for one languid sub-adult. Although actual flying time ranged pretty close to 11 days for all the cranes, the slower birds spent up to two weeks at select stopovers while the quicker ones spent very little time on the ground.
The purpose of the GPS banding system is to try to determine the causes of crane mortality during migration, explained WBNP wildlife biologist Rhona Kindopp.
Thankfully, all of the 12 banded birds made both the southern and northern migrations safely, Kindopp said.
But scientists working on the migration study figure eventually one of the banded birds will die along the migration route, allowing them to gather the carcass and identify the cause of death.
“In the past we’ve had no idea what caused some birds to die during migration,” Kindopp said.
In the past three years 65 cranes have gone missing during migration, and only two carcasses have been recovered.
An additional 10 to 12 whooping cranes from the flock will be banded in August, when biologists with Canadian Wildlife Services (CWS) and United States Fish and Wildlife will visit WBNP.
The plan is to band a total of 60 birds from the flock, which is the last wild migrating flock of whooping cranes in North America.
Late last week, CWS scientists arrived in Fort Smith to start nesting surveys of the whooping cranes.
They flew over the nesting grounds in the northern section of WBNP during a three-day period on the weekend, and expect to have results later this week.
Those results will inform biologists on the state of the flock, which has risen from an all-time low of less than 50 birds in the 1960s to last year’s total of 262 birds, including a record 72 nesting pairs.
Meanwhile, on the ground in the NWT, the whooping cranes have continued expanding their nesting range outside of WBNP.
A third pair of whooping cranes established themselves for the first time this year at the fox holes, west of Fort Smith, on Salt River First Nation reserve land.
One of the oldest whooping cranes in the flock, named Lobstick, has nested at the fox holes since 1982. In 2004, a second pair of whooping cranes joined him and his mate.
Kindopp said the whooping cranes are territorial, returning each year to the same nesting area – roughly four square kilometers.
New nesting pairs must find a place to nest away from other birds, meaning that as the population continues to grow their nesting grounds will also spread.