Researchers are worried a lack of adequate wetland means endangered whooping cranes are migrating in larger-than-normal flocks, leaving them more susceptible to mass mortality.
That’s the bad news. The good news is the cranes spend some of their year in and around Wood Buffalo National Park, where local experts say they still have room to spread out.
Rhona Kindopp is Parks Canada’s manager of resource conservation in Fort Smith. She says once the cranes make it to Wood Buffalo National Park, they each have nesting space that can be from two to five square kilometres in size.
That reduces the risk of disease or a natural disaster harming their numbers.
“They’re quite territorial, like they are on the wintering grounds, but even more so on the nesting grounds, so they are quite dispersed,” said Kindopp.
There are only about 500 whooping cranes in the wild, migrating each year between wintering grounds at the Aransas National Wildlife Refuge in Texas and their breeding grounds in Wood Buffalo.
Typically the birds migrate alone, in pairs, or in families or small flocks, noted lead researcher Andrew Caven and his team in a recent paper. The study examined the apparent increasing size of crane groups crossing America’s great plains.
While the whooping crane population has been increasing – up from just 22 wild cranes in the 1940s – Caven believes migratory flock size is increasing at a rate that exceeds population growth.
That means if a natural disaster or disease swept through the flock, it could kill a huge number of the still-small population.
Telemetry to illuminate how flocks disperse
Kindopp said larger flocks haven’t been recorded by Fort Smith residents in recent years, even as an increasing number of cranes have been observed.
This tallies with Caven’s research, which found large numbers of the cranes were most likely to congregate in the centre of the migration corridor between Texas and Alberta.
Kindopp did, though, note the remoteness of Wood Buffalo National Park affects our ability to observe the cranes’ behaviour.
“We’re not observing them come into the park because the park is so big and there’s just not people everywhere to make those kinds of observations,” she said.
That means we don’t know when exactly the birds start to disperse into smaller groups or pairs.
As researchers mark more birds with cellular telemetry units – technology that tracks birds’ locations – they’ll have a better idea of what the cranes’ migration looks like in remote areas.
Counting cranes under Covid-19
As for a natural disaster taking out some of the whooping crane population in the national park, Kindopp says that has always been a concern – but as the population grows, it has lessened.
“Natural disasters can take many different forms. In the park, the habitat that they’re in is very remote and forest fires are a natural part of that landscape,” she said.
“And so the birds are adapted to being in that landscape, and therefore, by default, adapted to a fire-type landscape.”
Whooping cranes are expected to begin arriving in Wood Buffalo National Park within the next few weeks.
Typically, Parks Canada works with the Canadian Wildlife Service to monitor the cranes in their nesting grounds in May. Officials are planning how to safely do that while abiding by Covid-19 restrictions.
“We don’t want to have that gap in that data set,” said Kindopp. “It’s a long data set, it’s an international collaboration between Canada and the US on protecting the species and promoting its conservation.
“So we feel getting that information is a necessity. We’re working hard to figure out how to do it.”
In 2019, 97 nests were recorded in May. Thirty-seven fledglings were counted later in the summer.
Winter 2019-2020 population survey results from the US Fish and Wildlife Service are not yet available.