Release Protocols

The primary purpose of rescuing any wildlife is to remove it from immediate danger (mostly human induced) and restore it to its natural, healthy state and by providing temporary assistance, make it capable of surviving on its own. Rescued animals must only be held captive long enough to ensure complete healing and self-sustenance. Since no rescue process is thought to be complete until the animal is returned back to its natural habitat, Release is considered as an integral part of Rescue.

Wild animals have an innate need for space and freedom. While some animals may be released immediately after intervention, some others may require extensive care and rehabilitation before being considered for release. Even those that seem overly dependent (often in the case of orphans) demonstrate the need to be free after an appropriate rehabilitation programme. Yet, there may always be a handful of animals that may, due to the nature or extent of their injuries and dependency after human intervention or assistance, be ill-suited to a life in the wild.

Criteria for release

Below are some crucial criteria that must be considered in detail before attempting to release any wild animal:

Health and body conditions

Any animal that is to be released must be in optimal health condition, both in mind and body. Nature has little room for the weak and all those in suboptimal conditions will be eliminated in the natural course of events.

Fledgling birds, for example, lose their baby weight upon fledging as they will be unable to fly with such weight. At this stage, they need plenty of space to exercise their flight muscles, practice sharp twists and turns; soon their body appears muscular instead of pudgy.

Emotional readiness

Although an animal may be in prime physical condition, it may not necessarily be emotionally ready to be on its own. Release must only be considered if an animal is ready both in mind and body. Some visible signs that the animal is ready for release include alertness, a natural flee response, assessment before trust, shyness, etc.

The ability to recoup after a threat is also imperative for any wild animal. An animal that goes into shock and falls limp at the sight of danger is certainly not one that is suitable for release. Every effort must be made to assist such an animal to regain its confidence and flee response. Time and patience are sometimes the best solution for such an animal.

I rehabilitate a lot of small animals from home. I have noticed several fledgling birds (across different species and ages) take off at night and fly into walls. Typically, these babies tend to go through three stages, each lasting a few weeks, before they are confident and independent:

a. Take off from their perch in the middle of the night and fly into a wall. Once they fall, they become limb and stay on the floor.

b. Take off, fall and then attempt to lift and get back to the perch. But they may not necessarily be able to get back to their perches, instead, fly into the walls a few more time and keep fluttering.

c. Once a little older, they are better able to lift off and make mostly make successful attempts at getting back to their perches.

d. Finally, they learn not to react to sounds and movements and rely on their natural camouflage. Even when unsure, they stay still and wait for danger to pass. This is the ideal stage showing independence and maturity. The bird can now be considered for release.

I very much doubt such sequence of events happen in nature, perhaps because baby birds are perched next to their parents and have the option of getting closer to the parent for security.

Fear of humans

It is most beneficial for any wild animal to retain its natural fear of humans. History has shown us, more than once, those animals or species that have little fear of humans are more likely to be persecuted and eliminated. Rampant poaching in many places accelerates this threat. A conscious attempt must therefore be made to ensure that any animal under care does not become habituated but retains its natural fear of humans.

Please refer to our page on Rehabilitation of wild animals for more information.


Disease, and the lack of treatment, not only reduces the animal’s chance of survival but also poses a threat to the other animals at the release site thereby causing further destruction and endangering a natural population. Every animal must go through a thorough health check-up and be treated for any existing disease before release into the wild.

Availability of a suitable release site

The selected release site must have all the resources [food, nesting, security, mating opportunity; other conspecifics for social species] for the animal to meet all its needs. In addition to having all necessary resources, the release site must not have an overabundance of the respective species – this again would cause a lack of resources. Releasing an animal in an unsuitable area may only lead to displacement or its premature death.

Releasing animals in unsuitable areas may also lead them into conflict with humans, further exacerbating any existing conflicts and dangers. When not able to meet its needs, any animal is likely to travel longer distances and potentially wander into human-dominated landscapes, posing a threat to humans and vice-versa. This threat is even more pronounced when the species in question is a large carnivore or a megaherbivore.

Timing of release

Many animals move seasonally in response to the available resources. The seasonality of the movements may either be locally, in response to the changes in a specific zone, or it may be across a biome for some species. Releasing even a fit animal in a seemingly appropriate environment but at an unsuitable time may result in its needs being unmet.

Some examples of the need to choose the appropriate season may be species migration or hibernation, lack of food in the summer months or excessive rains in the monsoons, etc. Nonetheless, each factor may also be exploited appropriately to maximize the animal’s survival. It is always prudent to seek expert guidance on species biology and movements before deciding on the time of release. 

Legal permissions

Legal permissions may be required to release an animal in a certain place. Existing laws often help indirectly in maximizing the release success for the animal or species in concern and the governing agency may be able to advise you of the most appropriate place for the release of the species.

Selecting a release site

Species distribution range and locally extant population

The very first step towards site selection will be the species distribution range. A good sign of the natural distribution of the species and its habitat viability is the presence of other individuals of the same species.

Nonetheless, you may have rescued an individual which is currently considered as an invasive in the area it is rescued from. Releasing it back in the area might not only be an inappropriate option but may also be considered illegal in some places. A species must never be unintentionally introduced to an area outside its distribution range as it may likely disturb the ecological balance of that place. Such an animal may be considered for placement in captivity.

Availability of resources

Ideally, any area within the species distribution range must be able to provide for the animal’s needs unless there is a great imbalance in the ecosystem. A conscious check must therefore be made to ensure that the area can support the animal or species in concern. The area must support and provide for the animal’s basic needs, which include food, shelter, safety, escape from dangers and mating opportunities.

Overpopulation and expansion

If the current population of animals in the selected site of release appears to be expanding and spreading out rapidly, it may be a potential sign of overcrowding and resource depletion. If the release is intended for more than a few animals, it will be most appropriate to consider an alternative site with better availability of resources and thus avoid imposing on an already stressed ecosystem.

Lack of immediate threats and danger

No animal must be released in a place or manner exposing it to grave immediate threats or danger. It the threats seem unavoidable, a secure manner of release, such as a soft release, may be preferred to maximize its chances of survival. Releasing an animal next to big roads with heavy traffic, big water bodies, an overpopulation of predators, etc. may only prove unsuccessful for the release programme.

In-situ acclimatization

Acclimatization is a process by which an organism adjusts to new a new environment or changes within the same environment. Exposing an animal to a new environment will also expose it to many unfamiliar and potentially dangerous situations. By allowing the animal to adjust and familiarize itself to the majority of the factors before release not only maximizes its chances of survival but also eases the transition to the new release site.

Site fidelity

Most adult animals instinctively return to their territories – to the place they recognize as their home, after release. Although this phenomenon hasn’t been studied extensively for every known species, animals are well known to make of use the sun, stars, temperature, seasonality, daylight hours, earth’s magnetic field, etc. to navigate their way back.

Animals are known to have travelled hundreds of miles to return to their ‘homes’. In doing so, they may have to cross many anthropogenic barriers and face numerous other additional dangers en route. Unfortunately, many are also known to have perished on this journey home.

Building familiarity with and fidelity to the new site before release has been used as an effective technique to ward off ‘homing instincts’. Keeping animals captive in-situ at the site of release has been used with great success to build fidelity to the new site. This is especially useful when releasing adult animals at great distances from the place they were last housed at or picked up from.

Method of release

Soft release

A soft release is a means by which an animal is gradually introduced or familiarized to a new environment before its eventual release in that location. This is a slow, gradual process that allows the animal to return to a safe resting place until it is ready to be completely independent. As a soft release process can be an extremely time consuming and often requires extensive resources, it might unfortunately not be feasible for all rescued animals.

It is ideal to opt for a soft release for hand-raised young whenever possible. Hand-raised young have to learn all new skills through a method of ‘trial and error’ as they have no adults to teach or demonstrate the essential survival skills by way of example. They also have to offset the effects of imprinting and hence require more time and protection before they are completely independent. A soft release thus maximizes their chances of survival.

A simple way to soft release any wild animal is to shift it in an enclosure at the site of release. The animal must be housed in the in-situ enclosure for at least a couple of weeks before a door or window is opened for the animal to venture out. In most cases, particularly in the case of young animals, the animals may rush out but remain close to the enclosure and return for food and safety. Gradually, the animal will move further away from the enclosure and return for shorter durations. Supplemental feeding may be continued outside the enclosure until the animal is completely independent. The timeframe for the release will depend upon the species in concern.

Hard release

A hard release is a means by which an animal is released into a new location without its being accustomed to the new environment. Animals that have been rescued as adults are able to cope better with a hard release as they have already learnt all the skills necessary for their survival. Although a hard release may be the most feasible method of release under certain circumstances, it is most often carried out as a result of insufficient resources.

The release

The simplest way to release an animal, especially when going in for a hard release, is to release it at or next to the preferred habitat. The transport crate must be placed with the opening facing the habitat. The door must be opened from the back of the crate – the handler must never place himself/herself as an obstruction between the animal and its path to freedom. It’ll be too scared to leave the box and you will keep wondering why it took so long to leave. In larger, more aggressive species, this might result in an uncalled for accident where the animal might mistake you for a threatening stimulus and try to attack in an attempt to escape.

Simply open the door and step back and give the animal some space. Give the animal time to evaluate its new surroundings and decide its path of exit. An animal must never be aggressively followed after its release – simply watch from a safe distance to ensure the wellbeing of the animal.

Post-release monitoring

If it has been decided to monitor the animals after release, the conditions of the release site must also be favorable to allow tracking and monitoring of the animal.

Although it may be ideal to monitor the animals post-release to keep a check on their survival and health, thus validating the protocol followed, it may not always be affordable or feasible to monitor them for long after release as it takes huge amounts of resources and manpower to monitor and track an animal.

All morphometric data of the animal must be recorded prior to release (without causing unnecessary stress to the animal of course). Extensive photographs of the animal’s coat (spots, stripes, etc.) must be taken. As the markings of most species are as unique as our fingerprints, these will help to identify the animal if the chance arises. A note must be made of any peculiar markings, notches, injuries, etc. which may help in identifying the animal at a later date.

If intended to track, animals may be marked in simple ways using paints, permanent markers, notches, tags, bands, rings, etc. or in more sophisticated ways using microchips, VHF or satellite collars, etc. Guidelines for appropriately marking different species of wildlife are available and must be followed strictly. No animal must ever be marked in way that it may hamper its movements or day-to-day activities or make it more visible to a predator.

Useful links

BIAZA (2005) Conservation Reintroduction

CCWHC and OIE (undated) Health risk analysis in wild animal translocations

IUCN Guidelines for re-introductions

Quarantine and health screening protocols for wildlife prior to translocation and release into the wild

RISC: Standards (1998) Wildlife radio-telemetry

RSG Guidelines for non-human primate re-introductions

RSPCA Release of wildlife

Re-introduction practitioner’s dictionary 1998

Wildlife International – Release

Wildlife Rehabber – Release criteria