The whale spotted last week off the coast of Angus and Aberdeenshire has been joined by a friend.
A second humpback was spotted in waters between St Cyrus and Johnshaven on Sunday evening.
It has been established that the first whale, which arrived a week ago, was one of the two whales that were at Ythan Estuary near Aberdeen a year ago.
It is yet to be confirmed whether the second whale is also returning to the east coast of Scotland but but Paul Smith, from British Divers Marine Life Rescue, which has been monitoring the whale said that would “make sense”.
He said: “The whale that was at St Cyrus initially was one that was recorded off Aberdeen last year.
“Last year it was later joined by another animal of the same species.
“It would make sense that the second whale might have been at Ythan last year as well.”
Hundreds of people were at St Cyrus Nature Reserve over the weekend hoping to catch a glimpse of the animals.
Seasonal ranger Willow Lohr said: “There were hundreds of people on the beach and on the cliffs looking out to the sea.
“I only saw one whale yesterday, about 30 metres from the shore.
“It seems that when the tide comes in is the best chance to see it clearly, which is late afternoon and early evening. Most people come with binoculars.
“There is a lot of excitement here, especially when it breaches.”
Mr Smith said that it’s not unusual for the whales to stay for several months if there is enough food.
The whale seen at Pettycur Bay in Fife earlier this year stayed in the Firth of Forth for more than three months.
Mr Smith said whales are likely to have migrated north to feed before travelling south to warmer waters to breed.
He said: “It’s probably two single males that have arrived — it’s all to do with migration.
“The humpbacks are renowned for migrating from the warmer tropical Caribbean waters and go up as far as Iceland.
“In the summer time they go north to feed and in the winter they travel to the warmer waters to breed. They will be bulking up ready for the mating season.
“They only hang around if there is food and there’s a lot of fish at the moment.”
British Divers Marine Life Rescue has urged people not to attempt to swim with or get too close to the whale due to its unpredictable nature.
