On 11 January 2010, Melbourne simmered in 43ºC heat. Spare a thought for the colony of Grey-headed Flying-foxes at Yarra Bend Park, who sweltered through the day without benefit of air-conditioning.

The flying foxes have several natural responses to the heat including drinking by splashing their bodies in the Yarra during a low flight over the river, then roosting and licking the water off their bodies, as well as seeking refuge under thicker vegetation, including in neighbouring gardens. But young flying foxes cannot fly to shady areas or dip into the river to cool off, and suffer a higher mortality rate than adults.

A group of more than thirty carers spent up to 12 hours at the flying fox colony at Yarra Bend Park, checking for signs of heat stress and, as the temperature rose, co-ordinating the heat stress assistance. They spent the day spraying flying foxes with a fine mist of water which they were able to lick off their fur and keep hydrated.

In some circumstances where large numbers of bats clung together in tight clumps, the careers needed to intervene, using sprays and gently encouraging the animals to disperse to prevent them from overheating.

The carers also use syringes of water/glucose to help re-hydrate the most severely affected animals. Those that responded well were released back into the colony but others were retained by the carers to be rehabilitated and released later when they had recovered.

The carers consisted of volunteers from several groups, including Wildlife Victoria and Friends of the Bats, and staff of DSE and Parks Victoria.