A two-year-old orca that spent more than a month circling a Canadian lagoon where its mother died has finally escaped into the open ocean. 

Wildlife officials spotted the two whales in March, as the baby refused to leave its mother that had died on the beach. 

Rescuers were in a race against time to free the whale that could have starved to death in the lagoon and had attempted to lure her out to open sea using whale calls and a sling.

But in the middle of the night, the whale named 'Brave Little Hunter' made her way out to sea of her own accord when the high tide reached the area.

Rescuers have hoped for weeks that the baby orca would leave the lagoon on her own and at about 2:30 a.m. on Friday she swam out of the lagoon at high tide, reaching the Espinosa Inlet that would lead her to the open sea.

The Ehattesaht and Nuchatlaht First Nations tribal members said the calf chose a 'clear and glass-calm, star-filled night' to swim out of the lagoon and under a bridge to the inlet.

'Today the community of Zeballos and people everywhere are waking up to some incredible news and what can only be described as pride for the strength this little orca has shown,' Ehattesaht Chief Simon John told CBC News on Friday.

He said the calf, named Kwiisahi?is (pronounced kwee-sahay-is) which means Brave Little Hunter, started eating the seal meat provided by the tribe last week and rescuers hoped she would follow a trail of food they left to lead her out of the lagoon.

Kwiisahi?is was seen playing near the bridge the night before she escaped the lagoon, and John told Coast Mountain News that he has high hopes for her to reintegrate into the sea.

'I think she's really healthy,' he told the outlet. 'There's a lot of footage out there of her being happy around the bridge area.' 

Rescuers will continue to follow and monitor Kwiisahi?is' progress to ensure she doesn't come into contact with people or boats and 'will encourage her out toward the open ocean where it is hoped that the Brave Little Hunter's calls will now be heard by her family,' the Ehattesaht tribe told Coast Mountain.

Earlier this month, teams were gearing up to strap the orphaned whale into a sling strapped to a helicopter to airlift her out to open waters, but the attempt was in vain after she dodged a team of 50 rescuers. 

They sought to lure the baby orca out of the lagoon using recordings of other orcas and Indigenous drums - all of which were unsuccessful. 

Now that the calf managed to escape the lagoon on her own, the Ehattesaht said: 'With this part of the challenge solved by kwiisahi?is herself, every opportunity needs to be afforded to have her back with her family with as little human interaction as possible.'

Kwiisahi?is' journey started on March 23 when she followed her mother into the lagoon and became beached.

Rescuers believed a mistimed attack caused her 14-year-old mom, named Spong, to become wedged in a depression near the shore.

After two hours of trying to rescue her, Spong died and a post mortem revealed she had been pregnant.

Spong's calf refused to leave the area where she died, often swimming in circles long after Spong's body was removed from the lagoon.

'It was absolutely horrible, especially because we knew the tide was against us from the start,' Glen McCall of Totem Excavating who received the call told The Guardian.

'We didn't have enough manpower,' he said. 'It just wasn't enough.'

Now Kwiisahi?is' escape is nothing short of a miracle for the rescuers and the Ehattesaht tribe who have worked tirelessly to move the calf to the sea and reintroduce her to her pod.

This story will become something of legend, with First Nations' leaders saying Indigenous people across Canada are writing new stories about Kwiisahi?is to reinforce their connection to the spiritual world.

'Events like these have a deeper meaning and the timing of her departure will be thought about, talked about and felt for generations to come,' the Ehattesaht said.