Staff members at the Charles Darwin Research Station on Santa Cruz Island and at the Galápagos National Park are crowing about their new arrivals–eleven mangrove finches hatched in captivity as part of a major effort to stave off the extinction of their species. The mangrove finch, rarest of “Darwin’s Finches,” has an estimated population of only 80, with fewer than 20 breeding pairs.
Between February 3 and March 3, members of the Mangrove Finch project team collected 30 eggs from the wild at Playa Tortuga Negra, on northwestern Isabela Island. The finches there are threatened by an introduced parasitic fly, Philornis downsi, that preys on the young nestling finches, causing up to 95% fatalities.
At present, scientists haven’t come up with an environmentally safe method for eradicating the fly, so the solution is to evacuate the finch eggs before they hatch and then rear the hatchlings in captivity until they can be returned to the wild safely. Efforts continue to find ways to get rid of the fly.
Eggs have been hatching over the past two weeks, according to a press release from the Charles Darwin Foundation. Chicks are being fed 15 times a day on a diet of scrambled egg and papaya, introduced wasp larvae, moth innards and passerine pellets.
This is the second year for the rescue project that added 15 young finches to the population last year. This time around, project team members encountered some unanticipated problems.
“It was exceptionally dry at Playa Tortuga Negra,” said project leader Francesca Cunninghame, and the mangrove finches were slower breeding, consequently we only identified 12 nesting pairs.”
We also experienced two days of high wind gusts, Cunninghame said, “which made climbing trees up to 18 meters (59 feet) into the canopy, overwhelming and dangerous.”
The Mangrove Finch project team is led by the Charles Darwin Foundation and the Ecuadorian Ministry of Environment via the Galapagos National Park Directorate, in collaboration with San Diego Zoo Global and Durrell Wildlife Conservation Trust.
Nicole LaGreco, a lead aviculturalist from The San Diego Zoo said, “With the success of last season, we were excited and eager to be asked to participate again this year. While this year has presented more challenges than last year, we are hopeful for another successful season.”