The trust described it as “incredibly difficult” to get a high-enough quality photo of the underside of a whale to visually confirm their gender, and usually the presence or absence of a calf was a guide.
Cowen said: “It’s actually, as you might expect, very difficult to figure out a whale’s gender.
“Normally, you’d have to get quite close to them, either diving underneath them or waiting for them to flip upside down and take a photo at just the right second.
“The chances of that are basically one in a million.”
They said it was “incredibly lucky” that the local wildlife watcher was flying a photography drone and managed to take an image of Pi flipping on her back.
“That photo, hopefully not too much to Pi’s embarrassment, has now been passed around an international group of cetacean experts,” Cowen said.
After analysing the picture, experts agreed Pi was female.