A whole city celebrated the sighting of a platypus in Lake Burley Griffin over the winter. It became a phenomenon talked about throughout Canberra and beyond.

But it now seems the migration of the beloved creature may have been a sign that it was in difficulty.

Waterwatch volunteer Anna van Dugteren testing the water at the Jerrabomberra Wetlands. Credit:Steve Evans

Scientists now believe the charismatic egg-laying mammal went to the lake in the centre of Canberra because its usual habitat was too dry to provide it with food.

The theory comes from a major survey of the creeks, rivers and lakes in the ACT region, which showed that their health worsened under the impact of some of the worst seasons on record.