Kimberley Purple-crowned Fairy-wrens survive floods with surprising resilience

Researchers have discovered most of the endangered western Purple-crowned Fairy-wrens living in a central Kimberley wildlife sanctuary have survived the historic flooding event which devastated the region earlier this year.

When the once-in-a-100-years floods hit the region, staff and researchers at the Australian Wildlife Conservancy’s Mornington-Marion Downs Wildlife Sanctuary were forced to evacuate by helicopter and to pause an 18-year study of the fairy-wren population.

When they returned to the sanctuary in May, Monash University reserachers discovered the Fairy-wren population had only slightly declined after the floods, recording just 14 less birds than in November 2022.

“About three quarters (74 per cent) of the adult birds that were present in a census of the population at the end of 2022 just before the floods are still alive now,” Monash University PhD student Ian Hoppe said.

“This survival rate is lower than we usually observe over the November to May time period, however it is not as devastating as we might have expected from such an extreme flood event.”

Researchers were also relieved to find 24 of the 67 breeding groups in the population had fledglings after all active nests had been washed away during the flood.

Multiple groups were also found to be breeding in May, one month after the end of the usual December to April breeding season.

“Although surprising to see that the birds are still breeding this late in the season, we’re not entirely shocked,” Monash University associate researcher Dr Niki Teunissen said.

“We have noticed that in wet years birds often keep breeding for longer. Presumably this is partly because in very wet years, floods frequently wash away nests and birds don’t breed successfully until later in the season.”

It comes after a 2020 Action Plan for Australian Birds identified increased flood frequency as a medium-level threat for the Purple-crowned Fairy-wren, which warranted further research as a high priority.