An orphaned killer whale recently released into her native Canadian waters is still having trouble in keeping with her family, preferring instead the company of boats, researchers say.

If there's an intriguing-sounding boat or something over there, she might split off and go over and rub on its hull

John Ford Canada's Department of Fisheries

The two-year-old whale, officially named A-73 but nicknamed Springer, became separated from her family group, or pod, as the whales began swimming at a higher speed in the Johnstone Strait near Vancouver.

"When they are moving along slowly, cruising or feeding, she is fine. When they left she resorted to her old habit of approaching boats," Lance Barrett-Lennard, a scientist from Vancouver Aquarium, said in a statement.

"It is when she is alone she seeks the companionship of boats."

Springer - who was captured off the coast of Seattle in May - was released on Sunday, after making a 12-hour-journey to Telegraph Cove in British Columbia in a special container on board a high-speed catamaran.

Scientists hope Springer will permanently stay with his family, in what is described as one of the first attempts to reunite a wild orca whale - as killer whales are also known - with its pod.

'Old habits'

The 545-kilogram (1,200-pound) whale swam near her pod for two days, but became separated on Tuesday.

The relocation cost more than $200,000 (AP)

She then approached a small boat and rubbed amiably against the hull.

"She still has this tendency, if there's an intriguing-sounding boat or something over there, she might split off and go over and rub on its hull," John Ford, whale expert from Canada's Department of Fisheries told the Associated Press news agency.

"It's something she did a lot in Puget Sound because she didn't have whales to associate with down there, so boats sort of became a replacement for that for social reasons," Mr Ford said.

Springer has attracted international attention since being discovered swimming in the busy shipping lanes of Puget Sound, near Seattle, in poor health last January.

She spent at least six months there, often swimming beside the passenger ferries going to and from Seattle.

Scientists believe she became lost after being separated from her pod. Alternatively, she could have been rejected after her mother died.

Researchers decided to capture her to nurse her back to health, partly because she was becoming too friendly with boaters in the area, raising fears that she could capsize a small vessel as she grew.