A new chick has hatched at Frankfurt Zoo, contributing to the conservation of a species that no longer survives in the wild. The female Socorro dove (Zenaida graysoni) hatched on August 10 and belongs to a species once found only on the Mexican volcanic island of Socorro in the eastern Pacific.
The breeding is particularly significant because of the chick’s parents. The male is genetically important to the conservation programme but is already seven years old and, according to the zoo, would normally be considered to have entered the post-reproductive stage.
“The chick — a female — hatched on August 10. Our genetically important male is already seven years old and is actually already in the post-reproductive phase,” explains Simon Rohner, curator at Frankfurt Zoo and responsible for its bird collection. “Breeding him with the significantly younger female requires a great deal of experience from the animal care team with these demanding birds, as well as close observation of the individual animals. To make successful mating possible, we gradually adapted the way we care for our two birds to their needs.”
A species surviving under human care
The Socorro dove is an island endemic, meaning that in the wild it occurred nowhere else in the world except Socorro Island, which belongs to Mexico.
The species was discovered in the 1860s and scientifically described in 1871. Its decline accelerated after 1957, when a Mexican naval station was established on the previously uninhabited island.
When expeditions by the California Academy of Sciences failed to find any wild Socorro doves during the 1980s, the “Socorro Dove Project” was launched.
The project rests on two main pillars: maintaining an international ex situ conservation population through the European Association of Zoos and Aquaria’s EEP, and restoring suitable conditions on Socorro Island for the species’ eventual return.
“The fact that a chick of this dove species, which is extinct in the wild, has now hatched at Frankfurt Zoo is a major breeding success, thanks in no small part to the great commitment of the zoo team,” says Ina Hartwig, Frankfurt’s Head of Culture and Science. “Frankfurt Zoo has coordinated the EEP for the Socorro dove for many years. It is therefore all the more gratifying that, with this year’s breeding success, we can make another very direct contribution to the conservation of this extremely rare species.”
Frankfurt Zoo has coordinated the European Endangered Species Programme (EEP) for the Socorro dove since 1995.
According to figures released by the zoo, 153 Socorro doves are currently kept at EAZA institutions, while only 222 individuals are listed in zoos and bird parks worldwide.
Preparing Socorro Island for their return
Maintaining the ex situ population is only one part of the conservation effort. European zoos, scientific institutions, the Mexican government and international partners are also working to restore the species’ habitat on Socorro Island and create the conditions required for reintroduction.
One of the major challenges has been the presence of introduced species. Feral sheep, which had negatively altered the dove’s habitat, have already been removed from the island. A project is also working towards removing feral cats, which were originally brought to Socorro by people living at the military base.
Cooperation with the Mexican Navy has helped make some of these measures possible, removing one of the obstacles to the planned reintroduction.
Work has also been underway for years to transfer young, reproductive Socorro doves from European zoos to Mexico, with the aim of establishing a breeding population there.
International transfers remain highly complex, however, due to requirements including animal disease prevention regulations and the extensive planning involved. Despite these challenges, the project succeeded several years ago in bringing Socorro doves back to a zoo on the Mexican mainland for the first time in 40 years.
The female hatched in Frankfurt now joins this very small global population, maintained with a long-term objective: creating the conditions for Socorro doves to eventually return to the island where the species once lived in the wild.
