Saving Babies from Extinction
How humans are helping to save a species
It’s wonderful to be able to share another great success for saving an endemic Galapagos species. The Charles Darwin Foundation (all photos attributed to the Foundation) has raised eight endangered mangrove finches and released them onto Isabela Island. This is a story I have followed for several years and have two earlier posts that show the evolution of the project. Read Galapagos Finches — From Darwin to the 21st Century and Let’s Save the Endangered Mangrove Finch.
I can remember growing up with mangrove finches and seeing them as I guided early morning panga rides through the mangroves on just about every cruise trip. But that once frequent event has changed and, for years, a mangrove finch sighting has been rare, if indeed we see one at all. That these important symbols of evolution are, with help from scientists, reviving, is a monumental step toward rejuvenation of the species.
Of all the Darwin finches, the mangrove finch is the rarest. Its population is estimated to be less than 100 individuals. Within these individuals, there are only 20 breeding pairs. And, equally significant is that even when the finches mate successfully, the mortality rate of the hatchlings has been a staggeringly high 95% because of the invasion of a parasitic fly, the subject of a previous post.
In February, scientists painstakingly and carefully collected eggs from mangrove finch nests on Playa Tortuga Negra and incubated the nest in conditions that mirrored those in the wild. Success! They hatched. Then the little fledglings were hand-reared until they were ready for independence. With tweezers they were fed morsels of moths, flies and other delicacies that their parents would have brought to them had they been able.
Even after they grew a little, the birds were not taken directly from their Santa Cruz baby nursery to the wild. Rather, for a period of three weeks, they were placed in what is called a pre-release aviary located inside the mangrove forest. There, they were able to start the adaptive process and get to know the environment of their soon-to-be permanent home. During this period, they were fed natural food eaten by the mangrove finch.
After three weeks, it was time for the experiment to continue. Tiny transmitters were placed at the base of the birds’ tail feathers to allow for monitoring. In addition, colored rings were placed on their legs for easy identification. The aviary was opened and the finches were allowed to come and go as they wished. Birds who returned found food waiting for them. Monitoring showed that at first most of the birds returned to the aviary. Eventually fewer returned as they adapted to the wild. Monitoring indicates that most of the juveniles stayed at Playa Tortuga Negra, but some went north and other south toward Darwin Volcano and Tagus Cove.
As for the success of the mangrove finch release program, Francesca Cunningham, project leader for the Mangrove Finch Captive Rearing Program, had this to say:
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.
Unfortunately, the parasite has not been eradicated yet, so those finches born in the wild and not nurtured by their human care givers still suffer from the high mortality rate. Still, steps are being taken to see that this unique and important species, while endangered, does not become extinct.
In fact, in August 2015, the journal New Scientist revealed that during field work in Galapagos, Sabine Tebbich of the University of Austria in Vienna observed that four difference species of Darwin finch were picking leaves from a Galapagos guava tree and rubbing those leaves on their feathers. Further study disclosed that the sap from the leaves repels invasive mosquitos and, by so doing, inhibit the growth of the “bloodthirsty parasitic larvae” that are threatening the baby finches. These findings were presented at the Behaviour meeting in Cairns, Australia, but remain tentative until further study and formal publication. The result, make the pesticide available to the endangered birds in the form of nesting material. Maybe the finches themselves will be able to aid in their future survival.
Harry Jiménez, Owner and General Manager
Galapagos Eco Friendly
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A version of this article has been published at blog.galapagosecolodge.net.