Australian flood disaster for migratory birds

CANBERRA - Flooding in South Australia has had a disastrous effect on migratory bird species, a leading expert said.

Nesting sites of the rare bird species which migrate to SA’s Coorong region have been damaged after the River Murray broke its bank in late December 2022, reaching its strongest flow since 1956 and flooding thousands of properties.

According to David Paton, an ecologist at the University of Adelaide, the number of birds nesting in the area is down 66 percent from early 2022 as a direct result of the high water.

There have been no egrets spotted in the Coorong’s lagoons, with Paton and his colleagues unsure of where the birds have gone.

In addition to damaging nests, the high water has also increased nutrients in the Coorong’s protected wetlands and decreased salinity.

An algal bloom in the wetlands is also limiting the food source for migratory shorebirds which usually flock to the region over summer.

“This is pretty disastrous if you’re a migratory shorebird because you have no mudflats in which to forage,” Paton recently told the Australian Broadcasting Corporation (ABC). “The birds are now limited to the fact they’ve got to forage on the tops of this rather yucky-looking, filamentous green algae,” he added.

Fiona Paton, David’s daughter and a fellow ecologist, said she does not expect any fairy tern chicks to hatch this season with their usual nesting sites currently underwater.

Native to the southwestern pacific, the fairy tern is officially considered a threatened species.

Since the 1990s, the number of fairy terns in the Coorong’s south lagoon has fallen from 1 500 to approximately 300. Paton has found only one nest in 2023, but said it is at risk of flooding.

“A change of direction of wind, or storms, or an increase in the water level will be enough to flood these eggs,” she said.