Researchers are citing a bumper crop of whooping crane twins as proof that the endangered species is making a comeback, although it's expected to stay on the endangered species list for many years.

A record 24 sets of the twins were born in Wood Buffalo National Park this year, where more than 200 of the big birds — they are 1.5 metres tall — now live. There were only 15 cranes 60 years ago.

A pair of 13-month-old whooping cranes at a refuge in Maryland.
(Roberto Borea/Associated Press)

And in May, the Canadian Wildlife Service located 62 nests, also a record, inside and outside the park, said CWS biologist Brian Johns.

"Yeah, things are really going well at this point," said Stuart MacMillan, who monitors crane habitat at the park, which consists of nearly 45,000 square kilometres that straddles the Alberta-Northwest Territories border.

Not only was the birth rate a record, but more birds are surviving than usual.

MacMillan said usually one of the twins won't survive, but lots of snow during the winter provided a lucky break.

"With enough water in the ponds where the cranes nest, the water itself might provide a bit of an impediment for predators trying to access the nest." 

But even with the bigger population, Johns estimated it will be at least 30 years before the cranes are removed from the endangered species list.