Nearly 40 days after the first mangrove finch eggs and chicks were harvested from their nests at Playa Tortuga Negra, it was time to send them home. Ever since they had arrived at the Charles Darwin Research Station in the Galápagos as young chicks or embryos yet to hatch, we had spent all of our time hovering over them and attending to their every need with one goal in mind: to send healthy mangrove finches back to Isabela Island for release. It was an exciting and hectic time as we prepared to transfer the oldest chicks while the younger chicks were still being fed every hour!
Pre-release aviaries had been constructed in the mangrove at Playa Tortuga Negra by local builders and awaited the arrival of the seven oldest chicks that would make up the first release cohort. After the remaining eight were grown and feeding themselves, they would join the first cohort in the aviaries.
Members of the first cohort were fitted with a unique combination of color bands on their right leg for identification from a distance as well as a silver, numbered band on their left leg. A drop of blood was drawn from under the wing of each bird (just like pricking a finger) for DNA sexing. Transport crates were inspected by the Galápagos Biosecurity Agency to ensure that quarantine conditions would be maintained during the chicks’ transfer. The gear the field team would take with them was sprayed with insecticide and put into quarantine before it was allowed to leave for Isabela.
Mangrove finches relax in their transport crates aboard the Galápagos National Park boat “Guadalupe River.”
The evening of our departure, we transferred the chicks from their fledging cages to mosquito-proof travel crates that we then covered with black sheets. Keeping the birds in the dark while traveling helps keep them calm as it simulates nighttime, when they are typically inactive. A small crowd of staff members from the research station and their children gathered outside of the lab to catch a glimpse of the chicks as we carried them to the truck that would take us to the dock. This group had supported us throughout the project, but due to the quarantine conditions in the lab, this was their only opportunity to see the chicks. The public turnout for the chick transfer was a touching reminder of the support we had received from so many to make the project a success. We loaded the chicks in their crates into a truck for the short ride from the lab to the dock where we took a small boat, or panga, to the Galápagos National Park boat Guadalupe River. The finches got their own bunk on the boat, and we were underway for Isabela.
We sailed overnight and awoke in the morning in the shadow of Volcan Darwin off the west coast of Isabela. After a rushed breakfast, we loaded the finches back into the panga and headed for the beach. The mangrove forest here is protected by a wide, black sand beach, but the porous lava bedrock lets the forest flood at high tide. Navigating the thick tangle of roots and branches is downright treacherous when the forest is flooded, so we were fortunate to land at low tide when the walk from the beach to the pre-release aviaries was relatively easy.
A wild mangrove finch visits the chicks in the pre-release aviary in the mangrove forest at Playa Tortuga Negra, Isla Isabela.
The first step toward getting the chicks used to their new surroundings was transferring them from their travel boxes into fledging cages identical to those they had lived in at the lab. These cages were hung inside one of the three large aviary chambers and allowed the chicks to have a look at their new home while still keeping them confined to a smaller space in case the novelty was too scary or overwhelming. They settled in quickly, and we spent the afternoon watching them while finishing up the fine details of the aviaries and filling in gaps.
Both of the local snake species had been spotted at the aviary site, and we hadn’t gone to all of the work raising these finches for them to be snake food! Rather than snakes, though, the chicks attracted the attention of two wild mangrove finches that came down to the aviary to check out the new arrivals! The wild visitors were the cherry on top of an exciting day that had gone almost precisely as planned. We bid the babies goodnight and went to set up our camp. I was only going to be at the field site for about a week, but the rest of the team would be there for two months, and there was a lot of food, water, and gear to be hauled and organized.
Chick #1 forages in the pre-release aviary on Isla Isabela.
The next morning we let the chicks out of the fledging cages to explore the full aviary. We had furnished their new home with rotten logs, strips of bark, and trays of leaf litter—all places that they would find food in the mangrove forest after their release. They set about busily exploring these new things. It was entertaining for the field crew to watch them interact and learn to navigate in the larger space and to see their foraging instincts kick in.
The next several days were mostly spent observing the chicks in the aviary, finishing the aviaries in preparation for the arrival of the second cohort of chicks, and watching wild mangrove finches at their nests. We even managed to trap and band one of the wild finches that kept coming around the aviaries to check out the chicks! The days were hot, and one afternoon as I was having a combination bath/swim in the ocean, a Park boat showed up out of the blue with instructions to take me to a cruise ship that would take me back to Puerto Ayora. I had to bid goodbye to the field crew, pack up my gear, and go with them right away because the ship was already underway, and we would have to catch it sailing down the coast of Isabela. It was an abrupt ending to a really special part of my Galápagos experience. I got to bring the first of our hand-raised mangrove finches back to their home forest and spend a week camping on a beautiful, remote beach flanked by volcanoes and surrounded by the spectacular wildlife of the Galápagos.
The first release cohort of hand-reared mangrove finch chicks gather together in the pre-release aviary.
I arrived back in Puerto Ayora the following morning and was immediately back in preparation mode. It was nearly time for the second cohort of chicks to be transferred to the release site. We went through the entire process once more, and a week later, Michelle Smith with the Hawaii Endangered Bird Conservation Program and Anita Carrion of the Charles Darwin Foundation sailed for Playa Tortuga Negra with the second cohort of chicks.
With all of the chicks grown and moved back to Isabela, there was nothing left for me to do but clean and pack up the lab and wait to hear from the field team. I could do that from San Diego, so I headed home, excited by what we’d accomplished but still nervous about how the chicks would fare after their release.
Beau Parks is a senior keeper at the San Diego Zoo. Read his previous post, Mangrove Finch Eggs Hatch: A World First!