A trial conservation translocation of the mangrove finch in the Galaopagos Islands, Ecuador

Summary

The mangrove finch (Camarhynchus heliobates), Critically Endangered with only about 100 individuals confined to two small mangrove patches on Isabela Island in the Galapagos, was the subject of a trial translocation by the Charles Darwin Foundation, Durrell Wildlife Conservation Trust and Galapagos National Park to test whether a new breeding population could be established away from introduced rat and parasitic bot fly threats. After rejecting captive rearing due to disease risk seen in a related species trial, the team captured ten finches over three days and transferred nine, five juveniles and four adults, by speedboat to Bahia Urbina, 25 km south, releasing all birds the same day fitted with radio transmitters and color rings. Within days the birds dispersed locally and largely remained near the release point, but one juvenile returned to the source site within two days, and by 11 months after transfer, four of the nine birds, including two adult males and one adult female, had been confirmed back at the original source population, with one adult male observed singing at the release site during the intervening breeding season. No breeding was confirmed at the new site, and the whereabouts of four birds, three juveniles and one adult female, remained unknown. Major difficulties included the release site's habitat differing from the source mangrove, the inability to reliably sex most released birds, and the short 22-day battery life of tracking transmitters. The project rates itself Partially Successful, noting the trial succeeded in proving transport feasibility and site suitability for feeding but failed to establish a new breeding population.