Saving Kauai's Honeycreepers
Since it began in 1993, the San Diego Zoo Global’s Hawaii Endangered Bird Conservation Program (HEBCP) has worked with over a dozen native bird species found only on the Hawaiian Islands. The conservation status of these birds ranges from non-endangered surrogate species to critically endangered species that are on the brink of extinction.
The past decade has seen a precipitous decline in two species of Hawaii honeycreepers, the akikiki and akeke‘e. These two small species of forest birds are found only in a remote area on the island of Kauai and the wild population has been monitored for years. Due to the declines of both species in the wild, bird experts determined these two species should be raised in captivity as a safeguard against extinction. Based on that decision and with funding from the US Fish and Wildlife Service, as well as a grant from the Mohamed Bin Zayed Species Conservation Fund, our HEBCP team began planning the techniques and protocols to safely and successfully add these two new species to our facilities on both the Big Island and Maui.
Whenever possible, the best scenario for bringing a species into captivity is to collect eggs from nests out in the wild. There are many reasons why this is the preferred method. By collecting eggs, you eliminate the chance of bringing in a disease that an adult bird might have into the captive flock. It can also be very difficult to teach an adult bird from the wild to eat from a food pan and acclimate it to a captive diet. Another reason we didn’t want to start our captive flock by collecting adult birds out of the wild is that there are so few akikiki and akeke‘e left in Kauai’s forests and we didn’t want to negatively affect the wild population. When you collect a wild female’s eggs she almost always builds a new nest and lays a second clutch. Thus, you can build a captive flock without reducing the number of wild chicks produced.
One of the first decisions made by our team was to setup an egg house on Kauai instead of trying to transport eggs from there to our facilities on Maui or the Big Island. Akikiki and akeke‘e eggs are incredibly tiny, weighing between 1.2 and 2.5 grams. As a comparison, two plain M&Ms weigh 1.8 grams! These eggs are so delicate that they could become damaged during transport if they were flown to another island. With generous help from Jesse Fukushima from Kauai Realty, Inc. as well as Bryan and Tanya Tanaka, we rented a house on Kauai and shipped over all the equipment and tools we would need to care for the eggs and chicks we hoped to obtain. This included everything from incubators and brooders for the eggs and chicks to the food items that we would eventually be feeding.
Our next task was to decide what incubation, hatching, and rearing methods to use for these two new-to-us species. We had to think of everything from what temperature we would use to incubate the eggs to what food items we would feed the chicks. Fortunately for us, the akikiki and akeke‘e are insectivores (meaning most of their diet comes from insects) which are very similar to two other honeycreeper species that we have already worked with, the Hawaii creeper and the Hawaii akepa. Thus, with some small adjustments, we adopted successful protocols we had used with the Hawaii creeper and Hawaii akepa to use with our new species.
We had the house, we had the supplies, we had the protocols…the only thing left to do was to collect the eggs! Unfortunately, this was much easier said than done. Akikiki and akeke‘e nest in the remote Alakai Swamp on Kauai. There are no roads into this habitat, it can only be reached by a long, arduous seven-hour hike through the rainforest. Yet, getting to the birds’ territory is the easy part. Akikiki and akeke‘e build their nests at the ends of branches, sometimes 40 feet up in the air! The big question was: how would we reach the nests to harvest eggs? The State of Hawaii’s Kauai Forest Bird Recovery Project (KFBRP) team identified a technique where a 40-foot ladder is raised to almost vertical and, instead of leaning against something, is then tied off onto anchors behind the ladder. This setup would allow our HEBCP staff to gain access to the nests that were previously too remote to collect from.
On March 26, 2015, after spending the previous day practicing the ladder techniques and transporting the ladder to the nest site, we set the ladder up and, with assistance from the KFBRP team, collected two eggs from an akikiki nest. The eggs were placed in a thermos and lowered from the nest by rope before being transferred into a battery-powered incubator. The ladder was then moved to a second akikiki nest and two more eggs were harvested and placed into the portable incubator, then carried back to camp on foot. A helicopter that was on standby was notified of our successful harvest and began flying to the landing zone near the camp. We carefully brought the eggs to the waiting helicopter and flew out of the swamp. The strenous hike into the location translates into a 20-minute helicopter ride to a landing zone just a few miles from the egg house. At the house, the eggs were weighed and candled. Candling the eggs is a process in which a bright light is shone through each egg to see which ones are fertile and how far along they are in development. With bated breath we candled our first egg. Inside, we saw active blood vessels and an embryo moving around—it was fertile! We candled the other three eggs and discovered the same thing. All four akikiki eggs were fertile and looked to be a few days away from hatching. We carefully put the eggs back into the incubator and let out a sigh of relief. We had successfully collected four fertile eggs from a brand new species of endangered Hawaiian honeycreeper, and if all goes well we should have four chicks in a few days time!
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Jeremy Hodges is a senior hospital keeper at the San Diego Zoo and seasonally participates as a research coordinator with the Hawaii Endangered Bird Conservation Program.