Flying foxes are very mobile mammals

Australia’s flying foxes are known for their nomadic lifestyle. Now, a new study has ranked them among the most mobile mammals on the planet.

However, their frequent flier status does have drawbacks, the researchers say, as it often puts them in conflict with humans. More and more are exploiting urban foraging and roosting resources, leading many to be treated as pests. 

“While it has been long recognised that flying foxes have the capacity to travel long distances, the vast scale and degrees of their movements among roosts shown by our study indicates that nomadism is in fact a fundamental aspect of their biology,” says Justin Welbergen from Western Sydney University, lead author of paper in the journal BMC Biology.

He and colleagues analysed the movements of 201 satellite-tracked flying-foxes from three species – 109 grey-headed flying foxes (Pteropus poliocephalus), 80 black flying-foxes (P. alecto) and 12 little red flying-foxes P. scapulatus) – across Australia for five years. 

They found that the flying-foxes travel thousands of kilometres among roosts each year, with one individual covering over 12,000 kilometres between 123 roosts over 1629 tracking days. 

Movements ranged from small relocations within roosts and foraging sites to nightly foraging trips of up to 80 kilometres and long-distance movements of several thousand kilometres.

“Our findings indicate that flying fox roosts are better viewed as integral parts of a network of staging posts that support highly dynamic populations of individuals that move in different directions and at different speeds,” says Welbergen.

“This contrasts with the conventional portrayal of a roost as being home to a recurring population made up of the same individuals.”

Flying foxes play an important role in dispersing seeds and pollinating flowering plants both locally and over vast distances as they fly roost to roost, and the researchers say their study highlights the need to understand their movements to support transboundary management and conservation.

“The extreme mobility means that impacts from local management actions can readily reverberate across jurisdictions throughout the species ranges; therefore, local management actions need to be assessed with reference to actions elsewhere and hence require national coordination,” they write.