Species reintroduction is the deliberate release of a species into the wild, from captivity or other areas where the animal survives. A species that needs reintroduction is usually one whose existence has become threatened or endangered in the wild. However, reintroduction of a species can also be for pest control. For example, wolves being reintroduced to a wild area because of an overpopulation of elk or deer. Because reintroduction may involve returning native species to localities where they had been extirpated, some prefer the term "reestablishment".

Reintroduction has been practiced for many years.

Principles of reintroduction

Reintroduction and translocation are both important tools for population and species management. Translocation moves wild-caught animals from one natural location to another, while reintroduction moves captive-born animals into their natural historical range. "Much of the behavioral research required to obtain reproduction will also be critical for reintroduction, which depends on the development of behaviorally competent individuals. More behavioral research to select the best candidates and prepare them for the very different challenges that await them in nature will be essential also. Behaviorists will again play a crucial role in post-release monitoring to determine the behavioral deficiencies that limit the success of reintroductions. There may be no other conservation action where the skills of behavioral researchers are more essential than reintroduction." In situ conservation means "on site". In-situ conservation is the conservation of species diversity within normal and natural habitats and ecosystems. The challenge in using in-situ methods is to expand our vision of protected areas to include multiple use and extractive reserves to develop new models for conservation. In-Situ conservation uses innovative proposals such as damaged ecosystems to preserve rare, endangered, and threatened species and to expand the range of options available for economic development. Ex-situ conservation means literally, "off-site conservation". It is the process of protecting an endangered species of plant or animal outside of its natural habitat. Capturing and relocating part of a population from a threatened habitat and placing it in a new location where it may have a better chance of survival is one example. Ex-situ conservation should only be used when In-Situ conservation cannot.


Zoos are one of the most conventional methods of ex-situ conservation. Depending on their size and location, zoos receive between a few tens of thousands to several million visitors annually. Zoos provide education to the public about the many endangered species and explain the factors contributing the threats they face in their native habitats. Through ex-situ conservation methods they provide protected specimens for breeding and reintroduction into the wild. It has been suggested that this method should be used only when necessary and when In-Situ conservation is not possible.

Successes and failures

Reintroduction biology is new and continues to be a work in progress. The IUCN/SSC Re-introduction Specialist Group & Environment Agency, in their 2011 Global Re-introduction Perspectives, compiled reintroduction case studies from around the world. 184 case studies were reported on a range of species which included invertebrates, fish, amphibians, reptiles, birds, mammals, and plants. Assessments from all of the studies included goals, success indicators, project summary, major difficulties faced, major lessons learned, and success of project with reasons for success or failure. The Siberian tiger population has rebounded from 40 individuals in the 1940s to around 500 in 2007. The Siberian tiger population is now the largest un-fragmented tiger population in the world. Yet, a high proportion of translocations and reintroductions have not been successful in establishing viable populations. Black footed ferrets in North America have also been a highly successful reintroduced species. Husbandry techniques were refined and the first successful captive breeding occurred in 1987. For this species, disease management in captivity is paramount and strict protocols are followed. Genetic management is closely monitored and ferrets are bred using a mean-kinship strategy which provides genetic diversity when bred in captivity. To prepare them for reintroduction into their new "wild" habitat, captive-born ferrets are placed in outdoor pens, simulating quasi-natural conditions with dirt burrows and live prey. Ferrets that receive pre-release conditioning in outdoor pens prior to release have demonstrated 10-fold higher survival rates in the wild than ferrets that receive no pre-release exposure. Ferrets are typically released in the fall during their natural dispersal and kits (young of the year) are the primary candidates.

Many factors can attribute to the success or failure of a reintroduction. Predators, food, pathogens, competitors, and weather can all affect a reintroduced population's ability to grow, survive, and reproduce. Animals raised in captivity may experience stress during captivity or translocation, which can weaken their immune systems. The IUCN reintroduction guidelines emphasize the need for an assessment of the availability of suitable habitat as a key component of reintroduction planning. Poor assessment of the release site can increase the chances that the species will reject the site and perhaps move to a less suitable environment. This can decrease the species fitness and thus decrease chances for survival. They state that restoration of the original habitat and amelioration of causes of extinction must be explored and considered as essential conditions for these projects. Unfortunately, the monitoring period that should follow re introductions often remains neglected.

Improving research techniques

A cooperative approach to reintroduction by ecologists and biologists could improve research techniques. For both preparation and monitoring of reintroductions, increasing contacts between academic population biologists and wildlife managers is encouraged within the Survival Species Commission and the IUCN. The IUCN states that a re-introduction requires a multidisciplinary approach involving a team of persons drawn from a variety of backgrounds. A survey by Wolf et al. in 1998 indicated that 64% of reintroduction projects have used subjective opinion to assess habitat quality. This means that most reintroduction evaluation has been based on human anecdotal evidence and not enough has been based on statistical findings. Seddon et al. (2007) suggest that researchers contemplating future reintroductions should specify goals, overall ecological purpose, and inherent technical and biological limitations of a given reintroduction, and planning and evaluation processes should incorporate both experimental and modeling approaches.

Monitoring the health of individuals, as well as the survival, is important; both before and after the reintroduction. Intervention may be necessary if the situation proves unfavorable. Population dynamics models that integrate demographic parameters and behavioral data recorded in the field can lead to simulations and tests of a priori hypotheses. Using previous results to design further decisions and experiments is a central concept of adaptive management. In other words, learning by doing can help in future projects. Population ecologists should therefore collaborate with biologists, ecologists, and wildlife management to improve reintroduction programs.

Survival skills

It may be very hard to reintroduce species into the wild, even if their natural habitats were restored. Survival techniques, which are normally passed from parents to offspring during parenting, are lost. The genetics of the species is saved, but the natural memetics of the species is not.

Beginning in the 1980s, biologists have learned that many mammals and birds need to learn a lot to survive in the wild. Thus, reintroduction programmes have to be planned carefully, ensuring that the animals have the necessary survival skills. Biologists must also study the animals after the reintroduction to learn whether the animals are surviving and breeding, what effects the reintroduction has on the ecosystem, and how to improve the process.

Still, a vast number of animals may need to be reintroduced into the wild to be sure that enough of them learn how to survive. For instance, in reintroducing houbara bustards into the wild in the United Arab Emirates, more than 5,000 birds per year are used.

Re-introduction Specialist Group (RSG)

The RSG is a network of specialists whose aim is to combat the ongoing and massive loss of biodiversity by using re-introductions as a responsible tool for the management and restoration of biodiversity. It does this by actively developing and promoting sound inter-disciplinary scientific information, policy, and practice to establish viable wild populations in their natural habitats. The role of the RSG is to promote the re-establishment of viable populations in the wild of animals and plants. The need for this role was felt due to the increased demand from re-introduction practitioners, the global conservation community and increase in re-introduction projects worldwide.

Increasing numbers of animal and plant species are becoming rare, or even extinct in the wild. In an attempt to re-establish populations, species can – in some instances – be re-introduced into an area, either through translocation from existing wild populations, or by re-introducing captive-bred animals or artificially propagated plants.

United Kingdom

Ongoing or successful programs

  • European bison to the UK – (ongoing)
  • Black grouse to Derbyshire – (ongoing)
  • Common crane to Somerset – (ongoing)
  • Corncrake to Cambridgeshire – (ongoing)
  • Glanville fritillary butterfly to Somerset – (successful)
  • European beaver to Scotland, England, and Wales – (successful in Scotland and Northern England)
  • Great bustard to Salisbury Plain – (ongoing)
  • Heath fritillary butterfly to Essex – (successful)
  • Ladybird spider to Arne RSPB reserve in Dorset, England – (ongoing).[14]
  • Large blue butterfly in the West and The South West – (successful and ongoing)
  • Northern goshawk – the existing UK population is believed to be derived from a mixture of escaped falconers' birds and deliberate introductions – (successful)
  • Osprey to Rutland Water – (successful)
  • Red kite in the Chiltern Hills, Black Isle, Northamptonshire, Dumfries and Galloway, Yorkshire, Perth and Kinross and Gateshead – (successful)
  • Red squirrel to Anglesey – (successful and ongoing)[15]
  • Reindeer to the Cairngorms in Scotland – (semi-domesticated; successful)
  • Scots pine to southern England – (unplanned, successful)
  • Silver-washed fritillary to Essex – (ongoing, locally successful)
  • Wild boar to several places in Britain – (accidental, successful)
  • White-tailed eagle to the Hebrides – (successful)
  • White-tailed eagle to the east coast of Scotland – (ongoing)

Planned or proposed programs

  • Brown bear in the Scottish Highlands – (proposed)
  • Elk to Great Britain – (proposed)
  • European lynx in Wales, England and Scotland (proposed)
  • Golden eagle in United States and Wales
  • Gray wolf in Scotland – (proposed)
  • Arctic wolf in northern Scotland
  • White stork – (proposed)
  • White-tailed eagle to England and Wales (planned – on hold while a suitable site is found)
  • Gray whale to Atlantic Ocean and Irish Sea (proposed – considered not feasible technologically and biologically. Two vagrant individuals sighted in the Mediterranean Sea in 2010 and off Namibia in 2013, the latter is the first confirmation of the species in the Southern Hemisphere.)

Other countries

Planned or proposed programmes

  • Asiatic Lion Reintroduction Project of Asiatic lion to Kuno Wildlife Sanctuary from their only home presently in the world at Gir Forest National Park. Kuno Wildlife Sanctuary is the chosen site for re-introducing and establishing the world's second completely separate population of the wild free ranging Asiatic lions in the state of Madhya Pradesh. It was decided to re-introduce the Asiatic lion in Kumbhalgarh Wildlife Sanctuary in Rajasthan. Some will be reintroduced in two locations in Gujarat.
  • Siberian Tiger Re-population Project was proposed in 2009 to reintroduce Amur tigersback to their former lands and including the former ranges in Central Asia once inhabited by their closest relatives, the Caspian tigers. In 2010, two pairs of Siberian tigers, exchanged for Persian leopards to southwestern Russia, were set to be reintroduced in Iran's Miankaleh peninsula. Currently, the big cats (one of them had died) are being held in captivity in Eram zoo. Siberian tigers were also proposed to be reintroduced to a suitable habitat near the international river of Amu Darya in Central Asia and near the Ili River delta in Kazakhstan. A rewilding project at the Pleistocene Park, part of the re-population project was proposed back in 2005.
  • Red deer - A programme was announced in 2013 to reintroduce the red deer to Armenia. 4 males and 11 females of the species will be purchased and transported to a breeding centre at Dilijan National Park. The World Wildlife Fund Germanyand Orange Armenia have provided the funds for the project.
  • Cheetah reintroduction in India is a project to reintroduce the cheetah in India. The Asiatic cheetah became extinct in 1947 when Maharaja of Surguja hunted the last three in the state of Rewa in central India. It was officially declared extinct in 1952 by the Indian government. Plans are going on to reintroduce the cheetah to two site in Madhya Pradesh (Kuno Wildlife Sanctuary and Nauradehi Wildlife Sanctuary) and in Rajasthan's Shahgarh Landscape. However, the Supreme court of Indiaput a hold on this project as they recommended to protect the endangered lions first rather than import cheetah from Africaor Iran. (On hold)
  • South China tiger - Captive tigers being re-wilded in Laohu Valley Reserve in the Free State province of South Africa under Save China's Tigers programme, will be eventually released back into the wilderness of China.

Ongoing or successful programs


  • North African ostrich in Morocco, Nigeria, Niger and Tunisia (ongoing)
  • Southern white rhinoceros in Kenya, Uganda and Zambia (successful)
  • South African cheetah in Swaziland (successful)


  • Amur leopard in Russia (successful)
  • Arabian oryx in the Sultanate of Oman (successful), United Arab Emirates (successful), Israel (successful)
  • Bornean orangutan in East Kalimantan, Indonesia
  • Indian rhinoceros in Pakistan (ongoing)
  • North African ostrich in Israel and Saudi Arabia (ongoing)
  • Nubian ibex in Israel (successful)
  • Eurasian otter in Japan (ongoing)
  • Père David's deer in China (successful)
  • Persian fallow deer in Israel (ongoing)
  • Persian leopard in Russia (ongoing)
  • Persian onager in Saudi Arabia (successful)
  • Przewalski's horse in Mongolia (ongoing)
  • Sarus Cranes in Thailand (ongoing)
  • Sudan cheetah in United Arab Emirates (ongoing)
  • Turkmenian kulan in Kazakhstan and Uzbekistan (successful)
  • Yarkon Bleak fish in Israel (successful)
  • Neurergus microspilotus in Western Iran (successful) 


  • Alpine ibex in the French, Italian and Swiss Alps (successful)
  • Eurasian brown bear in the Alps (ongoing)
  • European beaver in several places in Europe (successful)
  • European otter in the Netherlands (ongoing)
  • European lynx in Switzerland (successful), and other parts of Europe (ongoing)
  • European black vulture in the Massif Central in France
  • Goitered gazelle in Protected Areas of Vashlovani in Georgia (country)(ongoing)
  • Golden eagle in Ireland (ongoing)
  • Griffon vulture in the Massif Central, France (successful), Central Apennines, Italy, and Northern and Southern Israel (ongoing)
  • Iberian lynx in Portugal (ongoing)
  • Lammergeier in the Alps (successful) Switzerland (successful)
  • Lesser kestrel in Spain
  • Lesser white-fronted goose in Sweden and Germany (ongoing)
  • Northern bald ibis in Austria and Italy (ongoing)
  • Peregrine falcon in Germany, Poland, Sweden and Norway
  • Red kite in Ireland
  • Western swamphen in the Mondego River basin, Portugal (successful)
  • White-tailed eagle in Ireland (ongoing)
  • Wisent in Poland, Belarus (successful) and other parts of Europe (ongoing)

North America

  • Black-footed ferret in Canada, United States and Mexico
  • California condor in California and Mexico (ongoing)
  • Fisher in Washington State (ongoing)
  • Grey wolf to Yellowstone National Park (successful)
  • Musk ox in Alaska (United States) (successful)
  • American flamingo to Anegada, British Virgin Islands (successful)
  • Whooping Cranes, including migratory population in the Eastern United States and non-migratory population in Lousiana (ongoing)


  • Woylie in Australia (ongoing)

South America

  • Giant anteater in Corrientes, Argentina
  • Guanaco in central Argentina
  • Puerto Rican parrot in Arecibo (ongoing)
  • Red-and-green macaw to Iberá Provincial Reserve, Argentina
  • Vinaceous amazon parrot to Parque Nacional das Araucárias, Santa Catarina, Brazil (ongoing)
Community content is available under CC-BY-SA unless otherwise noted.