Reviving the Sihek: How Global Collaboration is Bringing the Guam Kingfisher Back from the Brink of Extinction

Reintroduction of Guam Kingfishers to the Wild

The reintroduction of the Guam Kingfisher, known as the Sihek, to the wild represents a pivotal moment in conservation efforts to restore species that have been extinct in the wild. The Sihek, a vibrant bird native to Guam, was driven to extinction in its natural habitat primarily due to the accidental introduction of the Brown Tree Snake in the 1940s. By 1988, the Sihek was no longer found in the wild, and the species' survival depended entirely on a small population held in captivity across several zoos in the United States.

The recent rewilding effort involves relocating a small group of Sihek to Palmyra Atoll, a remote and predator-free island in the Pacific Ocean. This site was chosen due to its absence of invasive predators like the Brown Tree Snake and its well-preserved ecosystem, making it an ideal location for re-establishing a wild Sihek population. The Palmyra Atoll, managed by The Nature Conservancy, offers a safe environment where these birds can breed and eventually thrive.

The relocation to Palmyra Atoll is part of the broader Sihek Recovery Program, a global collaborative initiative involving multiple organizations, including the U.S. Fish and Wildlife Service, The Nature Conservancy, and several zoos. The first cohort of nine Sihek, which includes birds hatched and raised under expert care, represents the initial phase of this ambitious reintroduction project. These birds will be closely monitored as they acclimate to their new environment, with the long-term goal of establishing a self-sustaining wild population.

The efforts on Palmyra Atoll are not just about re-establishing a wild population but also about gathering crucial data on how the Sihek behaves in a natural setting after decades of captivity. This information will be invaluable when considering the future reintroduction of the species to Guam, its original homeland. The project also reflects broader conservation goals of reversing the extinction trends caused by invasive species and human activities, using science-driven approaches to restore ecological balance.

This initiative is a significant milestone in conservation, marking the first time in nearly 40 years that the Sihek has a chance to live and breed in the wild. The success of this project could lead to further efforts to return the Sihek to Guam, where the ultimate goal is to restore the species to its rightful place in the island's ecosystem. The Sihek’s return symbolizes hope for the recovery of Guam's natural heritage and demonstrates the power of global collaboration in conservation​

Collaborative Conservation Effort

The collaborative conservation effort to save the Guam Kingfisher, also known as the Sihek, represents a significant achievement in modern conservation. This effort, led by the Association of Zoos and Aquariums (AZA) through its Species Survival Plan (SSP), brings together more than two dozen zoological organizations across the United States. The National Aviary, one of the leading institutions involved, plays a pivotal role in this project.

The SSP for the Guam Kingfisher was established to manage the breeding and care of this species, which has been extinct in the wild since the late 1980s due to the introduction of the invasive Brown Tree Snake on Guam. The goal of the SSP is to maintain a healthy and genetically diverse population in captivity with the ultimate aim of reintroducing the species into the wild.

This conservation effort is highly collaborative, involving a range of partners including the U.S. Fish and Wildlife Service, the Guam Department of Agriculture, and international organizations like The Nature Conservancy. The Guam Kingfisher population under human care has been meticulously managed to ensure the survival and eventual rewilding of the species. For instance, the birds are bred in facilities across the country, with significant efforts made to monitor and enhance genetic diversity, a critical factor for the species' long-term survival.

The recent successful relocation of nine Sihek to Palmyra Atoll, a predator-free island in the Pacific, marks a major milestone in this conservation journey. Palmyra Atoll serves as a trial site where the birds can acclimate to a wild environment before any potential reintroduction to Guam. This relocation is not just a logistical challenge but also a carefully planned conservation strategy, involving extensive research and on-the-ground monitoring to ensure the birds can thrive in their new environment.

The ultimate objective is to establish a self-sustaining population of Guam Kingfishers in the wild, potentially reversing their status from "Extinct in the Wild" to "Critically Endangered," which would make them one of the few species ever to achieve such a recovery. This project exemplifies the importance of collaborative, science-based conservation efforts and the role that zoos and aquariums can play in reversing the decline of endangered species.

The conservation work being carried out for the Guam Kingfisher is a testament to what can be achieved when global institutions work together toward a common goal. The ongoing monitoring and annual releases planned at Palmyra Atoll will be crucial in determining the success of this rewilding effort, with the hope that one day these birds will once again inhabit their native forests on Guam

Historical Impact of the Brown Tree Snake

The Brown Tree Snake (Boiga irregularis), an invasive species accidentally introduced to Guam in the mid-20th century, has had a catastrophic impact on the island’s ecosystem, particularly its native bird species. This snake likely arrived on the island shortly after World War II, stowed away in military cargo. Since its introduction, the Brown Tree Snake has become a dominant predator, causing the extinction or severe decline of nearly all of Guam’s native bird species.

The impact of the Brown Tree Snake on Guam's avifauna is profound. Out of the 25 resident bird species, 22 were severely affected, with 12 species likely extirpated as breeding residents on the main island. The Guam Kingfisher, known locally as the Sihek, was one of the species most affected. By the 1980s, the Sihek was extinct in the wild, surviving only in captivity thanks to a few individuals rescued and placed in breeding programs.

The ecological consequences of the bird population decline extend beyond the loss of the birds themselves. Native birds like the Guam Kingfisher played crucial roles in the island's ecosystem, including seed dispersal and pollination. Their disappearance has disrupted these processes, leading to significant changes in the vegetation and overall health of the ecosystem. For example, certain tree species that relied on birds for pollination and seed dispersal are now struggling to reproduce, which could lead to long-term ecological shifts on the island.

Efforts to control the Brown Tree Snake population have been extensive but challenging. Various strategies, including trapping, the use of snake-sniffing dogs, and aerial drops of toxicants, have been implemented to reduce snake numbers and protect the remaining native species. However, completely eradicating the Brown Tree Snake from Guam remains an elusive goal. The ongoing presence of these snakes continues to pose a threat to any efforts to reintroduce species like the Guam Kingfisher back into their native habitat.

The reintroduction of the Guam Kingfisher to the wild, therefore, hinges not only on successful breeding programs but also on effective long-term control of the Brown Tree Snake population. Conservationists are hopeful that with continued research and improved control methods, it may one day be possible to create a safe environment for the Sihek and other native species to thrive once again on Guam​

Journey to Palmyra Atoll

The transportation of Guam Kingfishers to Palmyra Atoll was a meticulously planned and executed process, critical to the effort of reintroducing this species to the wild. The journey began with nine Sihek, as they are locally known, being carefully raised and monitored in a biosecure environment at the Sedgwick County Zoo in Kansas. These birds were part of a larger collaborative effort under the Species Survival Plan (SSP) managed by the Association of Zoos and Aquariums (AZA). The SSP is designed to maintain genetically healthy populations of endangered species like the Guam Kingfisher.

The transfer process itself involved significant logistical challenges. The birds traveled over 4,500 miles from Kansas to Palmyra Atoll, a remote and ecologically pristine island in the Pacific Ocean, located about 1,000 miles south of Hawaii. The atoll was chosen as a temporary refuge due to its absence of predators like the Brown Tree Snake, which had decimated the Kingfisher population in Guam. Palmyra Atoll offers a safe environment where the birds can begin to acclimate to wild conditions, gradually preparing them for full release.

Upon arrival at Palmyra, the Kingfishers were housed in specially constructed aviaries where they could continue to be monitored and cared for by expert bird keepers. These aviaries provide a controlled environment where the birds can adjust to the local climate and begin exhibiting natural behaviors in a semi-wild setting. The birds are fitted with tiny trackers to allow conservationists to monitor their movements and ensure their safety as they explore their new habitat.

This process of acclimatization is a crucial step in the larger goal of establishing a self-sustaining wild population of Guam Kingfishers. The long-term plan includes releasing additional birds in the coming years to form stable breeding pairs, which is essential for the species' recovery. The success of this reintroduction effort at Palmyra Atoll is seen as a stepping stone toward the ultimate goal of returning the species to its native habitat in Guam, once effective control measures for the Brown Tree Snake are in place.

The transportation and rewilding process of the Guam Kingfisher at Palmyra Atoll is a testament to the collaborative efforts of numerous organizations, including the National Aviary, The Nature Conservancy, and the U.S. Fish and Wildlife Service. These efforts represent a significant milestone in the global fight to prevent the extinction of critically endangered species and to restore ecological balance to regions impacted by invasive species.​

Future Steps for the Species' Recovery

The future steps for the Guam Kingfisher, or Sihek, involve a careful and strategic approach aimed at establishing a self-sustaining wild population, primarily on Palmyra Atoll. This initiative is seen as a crucial step toward the species' eventual return to its native habitat on Guam, which remains compromised due to the presence of the invasive Brown Tree Snake.

The reintroduction on Palmyra Atoll is part of an experimental population strategy under the U.S. Fish and Wildlife Service’s section 10(j) rule, which allows for the release of endangered species outside their historical range when their original habitat has been irreversibly altered. The initial release of nine Sihek to Palmyra represents a significant milestone, as it marks the first time in nearly 40 years that these birds have lived outside of captivity.

The long-term plan involves monitoring and supporting these birds as they adapt to their new environment. Scientists will use this period to gather critical data on their behavior, diet, and interactions with the ecosystem, which will inform future conservation strategies. The goal is to refine the techniques for release, ensuring that the Sihek can survive and reproduce in the wild. These efforts will be repeated annually, with additional birds being introduced to build a stable population.

The ultimate objective is to increase the global population of the Sihek significantly, with Palmyra Atoll acting as a temporary but crucial refuge. This site allows for close observation and intervention if necessary, providing a controlled environment where the birds can be supported through the early stages of their rewilding process. The hope is that once the population is robust and the threat of the Brown Tree Snake on Guam is mitigated, the Sihek can be reintroduced to their original habitat.

This project is not only a key part of the Sihek’s recovery but also serves as a broader model for island species conservation. Islands are hotspots for biodiversity but are also highly vulnerable to invasive species and other threats. The success of this project could inspire similar conservation efforts globally, helping to prevent extinctions and restore ecological balance in fragile island ecosystems.

The collaboration between multiple organizations, including the U.S. Fish and Wildlife Service, The Nature Conservancy, the Guam Department of Agriculture, and various zoos and conservation bodies, highlights the complexity and importance of this endeavor. By working together, these groups aim to secure a future for the Sihek and, eventually, see it once again thriving in the forests of Guam.

Sources:

ZSL, The Nature Conservancy, All About Birds, USGS, The Wildlife Society