Eight chicks belonging to a dove species that has been extinct in the wild for decades have successfully hatched at Chester Zoo - boosting survival hopes for the incredibly rare birds. Today, all remaining Socorro doves are cared for in zoo conservation-breeding programmes across Europe and North America, which are working to pull the species back from the brink. Approximately 200 birds represent the entire surviving population, but bird experts have revealed that eight chicks (known as squabs) have hatched at Chester this summer. Some are now fully fledged, and there is a chance another clutch of eggs might be on the way. Chester Zoo, a conservation charity, cares for two breeding pairs of Socorro doves and supports the wider conservation-breeding effort. Socorro doves originally lived on Socorro Island off the coast of Mexico, but a mixture of factors led to their extinction in the wild. Andrew Owen, head of the bird department at Chester Zoo, said: "Historically, the Socorro dove had few natural predators, and the island remained uninhabited by people. Sheep introduced in the 1800s caused extensive damage to the wild vegetation and in 1957 a naval base was established on the island. Naval staff and their families brought domestic cats which became feral and caused tremendous damage to the native wildlife, including the Socorro dove population, which was last seen in the wild in 1972. "Sadly, the Socorro dove was overlooked by conservationists for many years and if it wasn't for the efforts of a group of German aviculturists, who created a breeding programme for the species, it would have been lost forever. In 1995, the Socorro dove conservation breeding programme was formally established when the European Association of Zoos and Aquaria (EAZA) approved it as a European Endangered Species Programme (EEP)." The Chester Zoo chicks will bolster the insurance population of Socorro doves looked after by avian specialists.