We built the present release cage in 2007 with the help of a Green Corps team, through Conservation Volunteers Australia and Atherton Shire Council. The team cleared the track into the colony, and carried in all the building materials – heavy railway sleepers, fencing panels, rolls of wire mesh and wheelbarrow loads of trench rock. It was a case of ‘many hands make light work’ with 10 Tablelands youth and their team leader Carlo taking 2 days to complete.
Most of the materials for the cage were recycled. It was designed with a ceiling about 50 cms lower than the roof to protect the bats’ feet from predators, and allow the outside bats to hang at a good height above the ground. We then need a small ladder to get the food up. There is a waterproof roof of UV stabilised plastic, and a waterproof shade cloth floor. We have two floors so that one can be taken home and cleaned properly every week. The floor is like a shallow swimming pool, it comes up the edges about 20cms. This contains the waste preventing rusting of the cage wall mesh. We scrape up the waste each day and remove off site or distribute in the forest several metres from the cage.
We usually start taking the pups out in late January to mid February. The first batch remain in the cage for about 5 days depending on weather, then they are let out and the next batch brought out. Initially the pups must be a minimum size of 145mm forearm and 450gms. We follow this procedure until all the bats are out at the release site and living free. The last bats to go out are usually a little smaller than the first, weights down to 350gms and forearms down to 135mm. It usually takes about 2 months to get all the orphans out to the release site becasue of the big disparity in ages. Any pup smaller than this is kept over for the following year.
We continue to feed daily for at least 4 weeks after the last lot of orphans go out. This is well into our wet season, and so the the rate at which we begin to cut back the food varies with the weather. The more cyclones and wet weather, the more food goes out. The wild babies have about 3 months of support feeding (breast-feeding) after they learn to fly, so we use this as the guide. We eventually cut back the food to once a week for the final month.