The white heron, or kotuku, is believed to have been visiting the area for the past few weeks.
Dunedin resident Jill Hamel said the appearance of the bird was good for the area but she was unsure why it had begun to visit more regularly.
''You'd have to ask the bird.''
It was a decent feeding ground, she said.
Dr Hamel used to walk the Andersons Bay area regularly and co-ordinated a project in 2009 to create a rocky islet for birds to roost.
Dr Hamel said the roost had improved the area for birds and its success had exceeded her expectations.
''I didn't realise it would make a real difference ... Nature always brings up surprises.''
White herons were not that uncommon. she said.
''There were a lot of them at Tomahawk. There were group of about seven of them about three or four years ago.''
Department of Conservation Coastal Otago ranger Jim Fyfe was aware of a white heron which had previously visited Tomahawk Beach.
''Whether this one is that one or a new one I couldn't say.''
The bird was relatively rare in New Zealand although it is common in Australia, the South Pacific and Asia.
A single breeding colony exists in New Zealand at Okarito Lagoon near Whataroa in Westland. There are about 100 to 120 of the birds in New Zealand, according to Department of Conservation statistics.
Mr Fyfe said the birds typically fossicked around the edges of inlets and estuaries looking for food.
