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How carers can enrich native fauna in rehabilitation and enhance their chances of post-release survival.

By Toni Mitchell & Jane Wilson


The American Zoo and Aquarium Association (AZA) define enrichment as:

"a process for improving or enhancing animal environments and care within the context of their inhabitants' behavioral biology and natural history. It is a dynamic process in which changes to structures and husbandry practices are made with the goal of increasing behavioral choices available to animals and drawing out their species-appropriate behaviors and abilities, thus enhancing animal welfare" (AZA/ BAG, 1999).

The Marsupial Society of Australia provides four aims of behavioural enrichment:

  1. To preserve and conserve natural behaviour e.g. searching for food in a particular manner, digging, climbing, browsing, foraging, caching etc.
  2. To eliminate or reduce levels of stress, abnormal or stereotypic behaviour, such as pacing, rocking, over-eating, aggression, hyper-sexuality or over-grooming.
  3. To increase the behavioural diversity of the animal by giving it a variety of different things that it can do and choices it can make, each day.
  4. To increase the animals' activity levels and thereby increase the overall levels of both mental and physical fitness.

They go on to discuss the benefits of providing various husbandry-based and environmental enrichment techniques to lessen negative behavioural patterns - a visit to their website is worth the look..


Current NT legislation dictates that any native fauna that comes into care has to be released, they are not pets. Therefore, all carers need to be mindful of the principles discussed and actively strive to provide the necessary environment to stimulate and encourage species-specific behaviours, for every animal in their care.

As carers who receive pre-release stage hand-raised mammals passed onto us for final preparation, we realised from the number of observed behaviours (or lack of) that some simple opportunities to provide these animals with survival skills and encourage species-specific behaviours are often missed by the first stage carer. This paper is written from personal experience, data sourced from research papers, research establishments and zoo environments. We predominantly sight native fauna, endemic to the Top End region, given that this is where we draw most of our personal observations and experience from. However, the enrichment principles applied to these animals in care/rehabilitation are easily adapted to other like species. It is essential that carers of wildlife have a sound understanding of the physiology of the species they take into care otherwise, how can we fulfil the needs of that animal? This basic knowledge and understanding is paramount if an animal is to be successfully released back into the wild.


In discussing enrichment, it should be clearly understood that this is a vital component of good animal rehabilitation practice and is essential for the animals' health and well being. Having a native animal in-care is not only about providing appropriate food, housing and shelter. We, as the provider of all things, can do much in the way of enriching each animal's time in captivity as well as building skills necessary for post-release survival. Providing enrichment and stimulation can help reduce boredom and stress often exhibited by abnormal behaviour or illness i.e. pacing, figure of eight, digging to escape, self-mutilation, aggression, recurrent incidence of disease etc.

There are a number of basic principles/practices that can be implemented to provide an enriched environment, thus affording each animal an opportunity to exhibit species-specific behaviours. It should be noted that this applies to all species be they birds, reptiles or mammals.

Research has shown the high levels of stress that POWs experienced under inappropriate and inhumane 'housing' facilities, essentially this is no different for any wild animal in our care. There is a plethora of information and research data available to anyone who cares to take the time and interest to look at what basic needs should be provided for animals in captive environments, in order to rehabilitate them for reintroduction into the wild. Research from zoo facilities constantly demonstrates the need to enrich and stimulate any animal in a captive environment, especially those species that are to undergo reintroduction 'into the wild'.

Every carer should strive to apply the principles of 'The 5 Freedoms' appropriately, as defined by the RSPCA (RSPCA Australia, www.rspca.org).

The Five Freedoms are:

  1. Freedom from hunger and thirst: by ready access to fresh water and a diet to maintain full health and vigour;
  2. Freedom from discomfort: by providing an appropriate environment including shelter and a comfortable resting area;
  3. Freedom from pain, injury and disease: by prevention through rapid diagnosis and treatment;
  4. Freedom to express normal behaviours: by providing sufficient space, proper facilities and company of the animal's own kind; and
  5. Freedom from fear and distress: by ensuring conditions and treatment which avoid mental suffering.


Below are a couple of quick ideas that are easy to do and may well make life more interesting for the animal in your care. These examples can be readily adapted for a variety of species (mammals, birds, reptiles).

Apple 'bobbing'!

Apples make cheap, simple, yet effective enrichment feeders, as well as providing a source of food on their own. Try pushing hard nuts into a sliced apple and hang from the roof or cage side, but be conscious of weight gaining foods and perhaps only feed once per week. Also, almonds are high in calcium and are not necessarily recommended for sub-adult and adult possums. This practice was successfully used with a possum that was preoccupied with trying to dig out of her trichiary this seemed to avert this behaviour and provided a positive distraction. Substitute a pine cone for the apple and push nuts, dried fruit etc into the crevices to be extracted. This will also occupy more of the animals' time.

Food accessibility

Provision of food should be such that an animal has to hunt for it, don't put their food in one container so that they go to the container, eat, and that is the end of the eating experience. Hook hard foods such as corn, carrots, cauliflower, broccoli etc and stash them amongst your bush tucker (which should be the main food source) so that they have to find each item individually. Make animals in-care work for it. Research on lab rats shows that they cope better if they have to actually find their food as opposed to having it presented all in one container with no effort on their behalf. This is part of the animals' opportunity to have control of their environment.

Frequency of feeding should be small amounts, provided often. Timing of feeds must mimic natural behaviours i.e. nocturnal animals fed at night. Food needs to be presented in such a way that each species must forage/seek as it would in the wild. Native food is seasonal and a variety of options should be presented to each animal at various times of the year bush tucker can be scarce, but that is what is available at the time and release candidates must be able to cope with the seasonal changes and what is available. Each animal has a 'time budget' relevant for that species and this should be pre-eminent in the mind of the carer i.e. possums are low metabolic, generally sedentary animals that have long sessions where they just sit, showing no activity this means they can easily become obese if fed inappropriately.

Therefore, if you feed more calories than the expended activity, the possum will become overweight and often susceptible to injury or disease. Most animals will not stay in a predicted home range but use an extended area to source nesting and food resources, this means that their environment is changing, therefore consider changing their environment whilst in-care by introducing novel structures into their facilities as this will assist them to cope with change once released.

Feed exclusively native bush tucker once or twice a week (no continental). Vary the foods offered i.e. mealworms, nuts spiked into apples, different choices of fruit, sugar cane, vegetables etc. Offer more vegetables than fruit as it has lower sugar content, leafy greens such as bok choy, spinach, Chinese cabbage (for example) are good options.

Dry rotting wood

Place rotting, dry, tree branches or trucks on the floor of the facility and scatter crickets, mealworms or larvae into crevices to encourage foraging.


Run rope through the facility, to provide an unstable climbing structure, with or without knots along it. Try to use natural fibres in case they are nibbled.

Sprinkler System

Encourages native grasses and potted plant growth. Simulates natural rainfall and creates flight response from animals when turned on.

Enclosure/Roof Top

Don't fully cover the roof as views of the skyline allows exposure to the elements, social interactions with resident animals and detection of threats by predators e.g. Rufous owls.


Different sizes and shapes, placed in different sites of the enclosure, provides climbing opportunities, hiding and observation sites.

Scented branches

Introduce foreign scents into an enclosure by taking a scented branch from one enclosure and putting it in another one. This has the advantage of allowing the use of branches from enclosures of other animals. It is important to note that there is a risk of cross-infection when moving branches from one enclosure to another so ensure each animal is in good health and not afflicted with any transmittable disease. Why not try aromatherapy? Cats are known to love Catnip, try different scents in your trichiaries i.e. vanilla, mint, etc sprayed onto branches.

Tree trunks

Placed in different positions (horizontal, vertical, at ground level) throughout the enclosure to encourage climbing skills, play and exploratory behaviour and scent marking.


Branches with leaves placed in the enclosure to resemble a living tree, provide perching sites and can be useful with destructive (chewing) species. They can be changed as needed. In 'the wild' branches of trees will fall and disrupt the thoroughfare of passageways, simulate this by moving branches round and 'challenge' in-care animals. We cut appropriate sized branches and place them in poly pipe with water as this keeps bush tucker fresh longer.

Potted plants

Different species of potted trees and bushes placed both inside and outside (for privacy screening). Preferably native species but, if not, must be non-toxic. Helps create a more natural environment and for arboreal mammals can be used to provide a climbing stimuli and natural behaviours, for birds it provides perching and a safe place to rest.

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