Rachel & Friends - Soft Release Part 3

Rachel & Friends - Soft Release, Part 3

A 'soft release' is where a flying-fox is released at a site that has support feeding.

This is usually the release site for orphaned young (who are now juveniles) that have not had the opportunity of a 'wild experience'.

Food is slowly decreased over a period as the juvenile bats start eating a wild diet, flight muscles get stronger as they fly further each night to forage for pollen, nectar and rainforest fruits.

These young flying-foxes can come and go until they are able to fend totally on their own. By then it is safe to remove all support food further encouraging them to join their wild family.

Guidelines for Management of Captive Flying-Foxes:

1. Make sure that there is access to sunlight:

The positioning of an aviary is so important. The animals need sun and air and space to fully open their wings and ensure that fungal infections such as ‘slimy wing’ do not develop. Toys, hanging drapes and native blossom will also add to the enjoyment of the captive animals in the aviary.

1. Management of Flying-foxes in an Aviary:

Animals must have appropriate companions in a suitable environment with adequate food.

When flying-foxes go into a captive environment, the hierarchy factor kicks in, for example males will be dominant over females and older bats will be dominant over younger bats.

More animals in an aviary will encourage competition for food.

If a lot of fruit is dropped to the ground and not plentiful enough, then the smaller and/or more submissive animals may feel the need to go to the ground to feed.

Going to the aviary floor to feed is not natural behaviour and should not be encouraged because it can lead to the following problems:

a. When the animal is released, the behaviour of scavenging for dropped fruit on the ground, will make that flying-fox vulnerable to attack by a domestic/feral cat or dog.

b. When a flying-fox is feeding on discarded fruit on the aviary floor, the under surface of their wings comes in contact with faecal waste containing bacteria, viruses and fungi. Later on when they try to clean their wings, these microbes are ingested. Given that these animals are already immunocompromised, from insufficient food being provided and distressed from dominant animals, it is inevitable that they will develop a condition such as 'slimy wing'.

3. Food & Water:

a. More flight activity in cold weather will mean captive flying-foxes will need more fuel than many of the husbandry manuals suggest. At least 450 gm, as a baseline, is required for an adult flying-fox and 300 gm for a juvenile flying-fox. However depending on the time of the year and how many bats there are in captivity, they may need even more food.

b. Offer fruit such as apple, pear, grapes, rockmelon. To make life interesting and to encourage flying-foxes, undergoing rehabilitation, to eat, offer small amounts of different tasting fruit such as paw paw, mango and banana. Only offer these in small amounts because of their high fibre content. The bulk of the fruit provided is primarily apple, pear and some melon.

Watermelon is helpful for keeping flying-foxes rehydrated during hot weather.

c. High protein supplement (HPS) must be mixed in with the chopped fruit. Wombarroo guidelines suggest that 15 gm HPS needs to be added to 300 gm of chopped fruit or 150 gm HPS added to 3 kg chopped fruit, if cutting large volumes. It is recommended that the volume of HPS should be increased for pregnant, lactating females, juvenile and debilitated flying-foxes to 20 gm HPS in 300gm of food. 

d. Watch the buckets carefully and remember that if there is no food left, several flying-foxes might have gone hungry. The amount of chopped fruit provided, in that instance, will need to be increased.

e. Water must always be available and changed on a daily basis.

Water can be offered in the guinea pig dispensers, as this provides a more interesting way of drinking rather than a bowl or bucket.

4. Environmental Enrichment:

Environmental enrichment is important for permanent care flying-foxes and can also assist in the healing process for wild flying-foxes following illness or injuries.

1. Toys can offer challenges and diversions particularly when it involves food. A ‘veggie basket’, available from pet stores, can be filled with pieces of soft fruit,
2. Kebab treat hangers can have fruit and leaves threaded onto them.
3. Fresh native vegetation with flowers and fruit can be added to the aviary or cage, as well as mulberry and eucalypt leaves.

(Credit: Sydney Wildlife Rescue & Care Training Course Manual, September 2020).

Summary:

So be vigilant, watch and observe the behaviour of the young flying-foxes and assess whether sufficient food is being offered.

If the buckets of fruit are empty the following day, offer more fruit to ensure that all the animals have access to sufficient chopped fruit, including high protein supplement powder (15 gms per bat) to ensure maximum health on release.

Photo credit: Marina Tretiach