Grey-headed flying-foxes (Pteropus poliocephalus) hanging in trees at a colony next to the Yarra River, These bats form part of a colony that was established here in early 2000's by the banks of the Yarra when the colony was moved from Melbourne's Royal Botanical Gardens. In summer, colony numbers can swell to over 40,000 from a population of around 5,000 over winter. Yarra Bend Park, Kew, Victoria, Australia. February.