Over 1,300 critically endangered Desertas Island land snails were released into the wild, in the Bugio Island in Madeira, Portugal. Almost driven to extinction by invasive species, these snails are the last of their kind on the planet.

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Chester Zoo has successfully bred the species in human care, and has since then sent them to other zoos - Bristol and Beauval - as part of a breeding programme. Reintroducing captive-bred individuals into areas where the invasive species that threaten them were eradicated is a vital part of the conservation strategy for the species.

Twenty four kulans were reintroduced into Kazakhastan's Torgai Steppe, part of a larger conservation initiative to reintroduce large herbivores to support biodiversity and ecosystems in the area. This species of wild donkey is listed as Endangered in the IUCN Red List, and Tiergarten Nürnberg has been supporting local organisations in conservation efforts to re-establish populations of this and other species in the region.

For the first time, five ‘alalā or Hawaiian crows were released into the wild, in the forests of Maui, Hawaii. The birds were bred and prepared for reintroduction at the San Diego Zoo Wildlife Alliance at Keauhou Bird Conservation Center in Volcano and Maui Bird Conservation Center in Makawao.

The species went extinct in the wild in 2002 due to habitat loss, predation and disease. Captive breeding and reintroductions are key components of the conservation strategy for the species.

An International Centre for Zoo Science has just opened at Chester Zoo, featuring Europe’s largest wildlife endocrinology lab, diagnostic tools and a biobank for threatened species. This centre has three main focus areas: Animal health and wellbeing, population sustainability, and human dimensions of conservation.

The Caldwell Zoo released twenty zoo-reared Attwater's prairie chickens into a wildlife refuge within their native range in Texas, USA. A critically endangered subspecies of the Greater prairie chicken, the Attwater's prairie chicken is threatened by habitat loss and overhunting, and the zoo has been involved in its conservation for over 20 years.