When a southern right whale made a rare visit to Wellington last year, the sight was enough to stop traffic.
Now scientists have raised the exciting possibility that such encounters could soon become more common if these ocean giants are rediscovering ancient migratory pathways.
It's a prompted a call for conservation authorities to ensure management strategies account for "animal culture".
This described how information – ranging from foraging behaviours and vocal dialects to migratory routes – was shared between birds, fish and many marine and terrestrial mammals.
University of Auckland researcher Dr Emma Carroll said the recovery of right whales around New Zealand was a good example of understanding what this meant for conservation.
In an earlier major study, she and colleagues revealed how migratory behaviour among the whales was learned by calves from their mother in the first year of life.
Calves were born in their mother's preferred wintering ground, and then travelled with their mother to her preferred summer feeding ground.
While mainland New Zealand long offered the species a good wintering ground – it's estimated there were once some 30,000 Southern right whales in our waters – that changed when whaling throughout the 1800s almost drove them to extinction.
"When right whales that visited mainland New Zealand in winter to breed and calve were killed off by whaling, the cultural knowledge of this area as a good wintering ground also disappeared," Carroll said.
"This is why we see many right whales in the subantarctic Auckland and Campbell Islands, but few around mainland New Zealand - the whales just don't learn about it anymore."
Because of our protection of the subantarctics, its New Zealand population had recovered to an estimated 2000 whales, as at 2009.
"There have been a handful of female right whales that have returned across years to calve around mainland New Zealand," she said.
"This means that the rare visitors, like the Matariki whale in Wellington Harbour in 2018, may be rediscovering migratory pathways back to the North and South Islands.
"The recovery of these whales depends on us making space for them in our coastal waters.
"This will allow whales that learn about mainland New Zealand as a good wintering ground come back and pass their knowledge to the next generation."
In a paper just published in major journal Science, Carroll and fellow researchers urged such behaviour to be considered in the scientific assessment and policy decision-making of international wildlife law.
Its importance was now formally acknowledged by the Convention on Migratory Species' scientific council, of which New Zealand was a signatory.
"Successful conservation outcomes can depend on the restoration of socially transmitted knowledge," Carroll said.
"For example, whooping cranes learn migratory routes socially, and human surrogates in microlight aircraft have guided captive bred birds along their first migration to help boost the success of reintroduction programmes."