Guidelines: Release of tigers
If a tiger is not being released back to where it was found, rehabilitators are strongly advised to consult the 2013 IUCN Guidelines for Reintroductions and Other Conservation Translocations for help and advice with planning and conducting all stages of the process.
Choosing suitable release sites is likely to be one of the most critical factors in successful rehabilitation, and advice should always be sought from experienced tiger biologists in the area concerned.
- All necessary federal and regional legislation must be considered, and permits obtained.
- The area for release must provide suitable habitat, a good prey base and access to other tigers (see habitat requirements in Basic Tiger Biology resource)
- A release site must not be near the rehabilitation facility. However, it may be necessary to construct a temporary release pen within a release site in the case of a soft release.
- Releases must have been thoroughly discussed with any local human communities and their agreement sought. Rehabilitators should not underestimate how long this may take.
Before release several decisions and preparations are necessary including:
- At 18 months tigers are generally considered to be able to hunt alone and be independent. Therefore, an 18-month-old cub could survive on its own if released when there is a lot of small prey available. However, in the case of tigers in the Russian Far East it would not be appropriate to release in winter at this age as the larger ungulate prey on which they depend would be far more difficult to catch.
- Before release tigers must demonstrate hunting ability and appropriate attitudes and reactions towards people. Abnormal behaviours that may hamper successful release and survival in the wild should be identified and a decision should be made on whether these behaviours can be corrected. If it is not possible, the animal in question should be removed from the rehabilitation centre.
- Opinions and experience differ as to whether to soft or hard release protocols are preferable. More documented experience in tiger rehabilitation will most likely be necessary to determine under what circumstances which option is best. A decision on this issue needs to be made well in advance of the release.
- A pre-release medical examination and assessment is desirable. This would involve physical examination, blood sampling for haematology and serum biochemistry profiles, and testing for specific disease where appropriate. Radio-collars can be fitted during this procedure.
- It is strongly advised that rehabilitated tigers are radio-collared prior to release to allow detailed post-release monitoring. Which type of collar to use depends principally on the questions being asked. GPS collars allow collection of multiple data points per day, allowing fine-scale analysis of post-release movement patterns. This is very useful in remote areas as data can be transmitted to researchers via cellular or satellite phone networks, but battery life is short compared to VHF collars. To document reproduction and mortality, having radiocollars that last 3 years or more is preferable and minimises the need to recapture. VHF collars can function for 4 years, but for large felids the use of aerial telemetry may be necessary to locate them, which is very expensive and risky for staff (Miquelle etal 2016). It follows that adequate resources must be available for post-release monitoring.
Transporting tigers to a release site also needs careful thought and preparation.
- All permits and documents applying to the transported animals, issued under the federal and regional legislation, should be obtained before transportation.
- Measures should be taken to minimise undue stress when tigers are caught from rehabilitation enclosures prior to transport. Careful design of the rehabilitation facility may allow tigers to be moved to smaller enclosures to allow quicker and more accurate darting. As few people as possible should be involved in the process, and noise should be kept to a minimum. The use of hides, pre-anaesthetic sedation, remote dartguns, and in the future perhaps drones, should be considered to make the process easier.
- In the Alexeevka rehabilitation centre, Russia, a specially designed safety vehicle is used from which to dart tigers in large enclosures. This also allows a degree of safety in checking the degree of immobilisation once an animal is darted.
- Box training to load tigers prior to transport to release site is not recommended as it is insufficiently aversive.
- Transport boxes/crates must be strong, preferably solid in construction (i.e. not open barred cages), dark inside, provided with good ventilation and a safe hatch to allow darting if necessary. In hot climates the box should remain cool, and in cold climates provide a degree of thermal insulation. There must also be a secure means of checking the animal visually during transport.
- Logistic issues should be given serious attention when preparing the animal transportation. All details should be considered and backup plans developed (e.g., what actions should be taken, if the vehicle has broken down; who will be dealing with the crate unloading on site; how quickly the crate with the animal can be carried to the release site in the forest, etc.). All these matters will affect the duration of the animal’s stay in the transport crate.
- The transportation time should be as short as possible to minimize transport stress.
- It is generally not necessary to provide food and water on short journeys. In case of the transportation of a healthy tiger to the release site, water may be withdrawn during the first 12 hours; afterwards, water should be given to the animal every 5–6 hours and more frequently in the case of small individuals and especially during hot weather. Provided that an animal has fed well before transport, food need not be given to small cats for 24 hours and to medium and large cats for 48 – 72 hours. The provision of food and water during transport requires safe access to securely fitted containers within the crates.
- If the transportation lasts for more than 5–6 hours, it is advisable to regularly check the animal’s condition.
- Transportation of animals by plane over the distances of less than 1,500 km is not reasonable because of complex logistics and remoteness of the airport from both rehabilitation centres and release sites. Transportation by helicopters is justified, if the animal can be transported directly to the release site.
A plan is necessary for non-releasable tigers well in advance. If an individual cannot be released to the wild, the only options are permanent captivity or, in countries and cultures that permit, euthanasia.
- Examples of conditions that could prevent a tiger being released to the wild include persistent conflict behaviour or apparent habituation to humans, blindness in both eyes, a fractured spine, the loss of a limb or foot, loss of function of a limb, infectious diseases that pose a threat to other tigers such as CDV, rabies etc, extreme old age and infirmity, fractures compromising effective joint movements, pelvic fractures in females that may cause dystocia at birth, etc
- A rehabilitation centre is not a suitable place for tigers held in permanent captivity.
- If it is decided to keep a wild-born tiger in permanent captivity it should be sent to a sanctuary or zoo that can provide high welfare standards – even if suitable places are in another country. Young tigers will adapt to permanent captivity much more readily than mature adults which are likely to experience far higher levels of chronic stress.
- Wild-born tigers that cannot be returned to the wild can play a very important role in international captive breeding programmes at zoos that can provide high quality care.
- It is not acceptable to place such animals in a sterile cage on public display where it will be subject to severe chronic stress.
- Nobody WANTS to euthanase tigers, but it may not be the worst welfare outcome for an animal. We should consider which is better: Long term captivity in a bad facility in which there is no possibility of adequate welfare standards (constant severe stress) or euthanasia?
- Euthanasia should always be followed by a thorough post mortem examination to learn more about the injuries and illnesses from which wild tigers suffer.