Mangrove finch/Pinzon de Manglar (Camarhynchus heliobates)

Mohamed bin Zayed Species project number 14259510

Saving the critically endangered Mangrove Finch of Galapagos from extinction

In 2014, the team from the Charles Darwin Foundation, with the Galapagos National Park Directorate and the San Diego Zoo, succeeded in raising 15 Mangrove finch hatchlings and returning them to their natural habitat on the west coast of Isabela Island, Galapagos.  Wild birds also contributed 6 offspring in 2014, meaning that the world population of this critically endangered bird is now increased by some 25%. 

In 2014 the collecting of eggs from the wild and captive breeding of mangrove finch chicks (Camarhynchus heliobates), a critically endangered species of the famous "Darwin's finches", began.

2015 field season

After the team from CDF and the GNPD arrived at Playa Negra Tortuga on Isabela Island, the fledglings were placed in the pre-release aviary located inside the mangrove forest, where they spent three weeks adapting to their natural habitat. Several sources containing the natural food of the mangrove finch were placed inside the aviary: branches, leaves and seeds of the three species of mangrove from the site (Avicennia germinans, Lacungularia racemosa, Rhizophora mangle), in addition to naturally occurring food items: Castela galapageia and Scutia spicata fruits, live moths and caterpillars in A. germinans seeds, as well as a range of invertebrates in leaf-litter. Additionally supplementary passerine pellet food also formed part of the diet of the birds.

After three weeks the aviary hatches were opened and the finches were free to come and go at will, the team continued to provide food inside the aviary for any birds that returned. Daily observations were made to record any birds visiting the aviary. Over time fewer individuals returned and they spent less time in the aviary as they adapted to being in the wild.

After their release, in order to facilitate short-term monitoring of the finches, tiny transmitters were placed at the base of the birds' tail feathers, the transmitter batteries lasted 19 days and remained attached during that time. Long-term individual identification is possible through colored rings placed on the legs of each individual.

During the release process, an additional nine-day-old chick was found dying in a nest infested with thirty three Philornis downsi larvae. The project team treated its wounds and raised the chick in the field and were able to release it back into the wild as a healthy fledgling.

The post-release telemetry monitoring showed the dispersion of most juveniles within the mangrove forest at Playa Tortuga Negra, however some individuals were found north towards Caleta Black and southward in the arid zone as far as the west side of Darwin Volcano and Tagus Cove.

Additionally, eleven wild nests from 10 pairs were monitored at Playa Tortuga Negra. Some pairs nested five or six times without producing fledglings while five pairs were successful and produced a total of six. Parasitism of P. downsi was the major cause of chick mortality and parasites were present in all monitored nests, including those which fledged, containing nestlings over three days old.

Francesca Cunninghame, Mangrove Finch project leader says:

"Releasing and monitoring eight mangrove finches bred in captivity, as they adapt to their natural habitat, is incredibly rewarding. Unfortunately, 2015 was a much more challenging year compared with our first attempt in 2014 and we have released fewer finches than hoped. However, eight young birds, released back into the wild once safe from the threat of P. downsi, is a significant boost to the juvenile population and from previous research we know that none of them would have survived as chicks in the wild. Each step of this process has been carried out in collaboration with our partners and we hope that by repeating and refining the techniques developed to date we can ensure the long-term conservation of this critically endangered species."

The release and consequent monitoring successfully completed the final stage of the 2015 captive rearing program that began in February and the results are positive for the mangrove finch population. Although the work to date represents just a step towards the long term conservation of the species, we remain committed to prevent the extinction of this unique species.

The Mangrove Finch Project is a bi-institutional project carried out by the Charles Darwin Foundation and the Galapagos National Park Directorate representing the Ministry of Environment. Our collaborators are San Diego Zoo Global and Durrell Wildlife Conservation Trust.

The project is supported by Galapagos Conservation Trust, Mohamed Bin Zayed Species Conservation Fund, Durrell Wildlife Conservation Trust, International Community Foundation (with a grant awarded by The Leona M. and Harry B. Helmsley Charitable Trust), Galapagos Conservancy, and the British Embassy in Ecuador.