Anthropogenic global warming is expected to cause major changes in the phenology of tropical rainforests in the short term and cause significant structural changes in the long term that will result in local species losses and possibly extinctions. Monitoring these changes is labour intensive and with steadily reducing funding for field environmental research, it is unlikely that such monitoring will take place, thus opportunities for some corrective actions will most certainly be lost. We propose to utilise flying foxes, Pteropus spp., which are large and highly mobile herbivorous megabats, as “flying monitors” of the changes to forest resources, by fitting them with GPS-logger collars. To allow us to economically track multiple animals with high spatial and temporal resolution, we have developed a solar-powered GPS-based logger, that following further size reduction small enough can be carried by an adult Spectacled Flying-fox Pteropus conspicillatus and costing less than one fifth of an Argos GPS-based system. This logger (capable of storing over 60,000 locations) will permit us to monitor detailed shifts in flying-fox feeding behaviour and energetics to monitor forest phenology with changing climate. Data are remotely downloaded without having to capture the animal or wait for the collar to fall off. Each collar has a radio-beacon to permit location of the animal for data download. Data from the loggers can be plotted on a GIS topographical and vegetation map data base.