The mangrove finch has been a focus of captive-rearing efforts for the past three years in the Galápagos Islands and it looks like all this work has been successful.
A captive-reared male mangrove finch has been observed singing in the wild, representing the first released bird to have been seen exhibiting this breeding behaviour.
“It is extremely encouraging to have confirmation of a captive-reared male exhibiting territorial behaviour,” said Francesca Cunninghame, the co-ordinator for the Mangrove Finch Project of the Charles Darwin Foundation.
“This observation shows that not only are the captive-reared birds capable of surviving long term in their natural habitat, but additionally they are likely to form part of, and increase, the mangrove finch breeding population – which is the goal of the head-starting programme.”
The mangrove finch is endemic to the Galápagos Islands and is listed as Critically Endangered by the IUCN Red List.
The global population consists of only about 100 individuals, which are confined to 32ha of mangrove forest on Isabela (the largest island).
The nestlings of mangrove finches are at risk from an introduced parasitic fly, Philornis downsi, and through predation by invasive rats.
The larvae of the parasitic fly feed on the blood of mangrove finch (and other birds) chicks. This often kills the bird, and those that do surive often have demormed beaks, reduced growth rates and anaemia.
Conservationists have been working to give the young finches a head-start by collecting eggs, rearing the chicks and then releasing the fledglings back into the wild.
Whilst the chicks are being reared, the wild parents can lay again which can double the odds of breeding success.
To date, 36 fledglings have been released back into the wild, with the singing male back in 2014.
“It’s exciting for us to see results like these,” said Sharon Johnson, chief executive of the Galápagos Conservation Trust, which has been the principal funder of the project. “However, we are aware that there is much more that needs to be done to ensure this species survives into the future.”
Listen to the mangrove finch’s song, recorded by the Charles Darwin Foundation.