Many rural landowners in their elder years may remember the odd and captivating sound made by greater sage grouse males as they courted females.
But the once-common sound — variously described as a soft booming, burbling or popping — has been rarely heard for decades as the greater sage grouse population fell to fewer than 200 birds.
In response, the Calgary Zoo has started a program to bring them back.
“A few years ago, it was brought to our attention that it might be useful to start a breeding and release program to start stabilizing populations in the wild, or even to recover them,” said Axel Moehrenschlager, the zoo’s director of conservation and science.
No one has attempted this before.
Last year, the zoo released 66 greater sage grouse bred in captivity into the wild and in October, released an additional 77 birds. They were set free near the hamlet of Manyberries in the province’s southeast corner and across the Saskatchewan border near Grassland National Park. The goal is to determine whether captive breeding for release can help preserve wild populations.
“We don’t believe that, that alone will solve everything, but we believe it can be a significant part of the puzzle,” said Moehrenschlager.
The greater sage grouse went extinct in B.C. three decades ago, but small populations still exist in Alberta, Saskatchewan and the U.S. Great Plains.
The birds are famed for their unusual, and elaborate, mating ritual, which takes place in spring on a patch of ground called a lek, a sparsely vegetated area with enough room for the males to put on their show.
“Basically, what happens during the mating season is that the males will show up on the dancing grounds,” said Moehrenschlager. “The males have this super-cool adaptation so they can puff up their chests with the air sacs and then they can let out that air in their chests and make a booming sound which echoes in a way that is supposed to be very interesting to the females.
“The females then show up and choose who their mates might be. That’s part of our natural heritage and something that older landowners have told me that they used to see far more. It’s almost non-existent in Canada now.”
The reason for the decline in greater sage grouse numbers isn’t fully understood. Hunting was once thought to be a factor but the birds, which are about the size of pheasants, haven’t been hunted for years.
“Understanding the reasons around their decline is very tricky, not just in Canada, but also throughout the States,” said Moehrenschlager.
Another theory is a change in habitat.
“They are called sage grouse because they depend on sage in the wintertime,” he said. “The physiology of their stomach changes so they can forage on sage in the winter and that’s kind of what carries them through winter.”
Most species that are endangered, like the greater sage grouse, are specialists, and do not adapt well to change or environmental pressures.
“Great sage grouse are very sensitive to disturbance. They need large tracks of grassland pasture. The grassland pasture can have cows on it, but it needs to be grassland.”
Biologists are currently tracking the sage grouse released into the wild by the zoo, which received support from the Nature Conservancy of Canada and Parks Canada for the project. Greater sage grouse in the wild have a low survival capacity — the likelihood that an egg will hatch and become a breeding adult is only about two per cent.
“A couple of the females that we were able to track survived right to the breeding season. We even saw one of them with chicks,” he said.
The team is tracking the second-year releases now, and are hoping they will make a big, positive impact on the population.
The greater sage grouse chicks are raised in a facility that is separate from the regular zoo facilities. A third of the eggs are hatched by parents, and two-thirds are hatched by zookeepers, who care for the fledgling birds. All are transitioned into bigger enclosures that allow them to fly and perform their mating behaviours.
“In everything we try to do, we try to maximize welfare, and simulate the natural conditions as much as possible, to facilitate breeding and producing birds that are suitable and good for release,” said Moehrenschlager.
But even if successful, the project will take years to bear fruit.
“We need to have effective releases for a number of years to help that population, because otherwise that population is on a trajectory to extinction in Canada,” he said.