Extinct in the wild birds raised by London Zoo keepers released into wild for first time in 40 years

 For the first time since the 1980s, six sihek (Guam kingfisher) are now officially living in the wild, in the tropical forests of Palmyra Atoll -  the result of global conservation project to restore the species. The birds’ successful release is  the result of years of work by the Sihek Recovery Program, a global collaborative of conservationists – including from ZSL - dedicated to reestablishing the sihek in the wild for return to its homeland in Guam.  These partners are internationally recognized leaders in animal care, conservation translocation, ecological restoration and wild population management and have applied their expertise to recover several other extinct in-the-wild species. 

Yolonda Topasna, DOAG Division of Aquatic and Wildlife Program coordinator said: “Our Guam Sihek, a symbol of our island’s beauty, with their cerulean blue and cinnamon coloration mirroring our ocean blue water and red-orange sunsets, have been achieving the seemingly impossible. Today, the Sihek were set free from their aviaries! Their return to the wild is a testament to our people’s spirit and our commitment to preserving our heritage.”  

Topsana added, “I’m sad to not be joining them at this milestone, however, I envision myself speaking CHamoru with them soon! To our Sihek, siempre un li’e’ iyon-måmi tåno’ yan tåsi. Nihi ta fan gumupu ya kumånta i CHamoru na kånta todu i lugåt (you will certainly see our homeland, our sea, and together we will fly and sing CHamoru songs in all places).”  

A total of nine young birds —four female and five male sihek — were hand-reared over the last several months at the Sedgwick County Zoo – with help from zookeepers from Whipsnade and London Zoos, both ZSL conservation zoos - for this historic rewilding.  

Although London Zoo is not home to sihek, the team’s expertise in raising other rare and endangered birds gives them knowledge to support work raising the chicks in Kansas earlier this year. Charlotte James, one of the London Zoo bird keepers who travelled to Sedgewick Zoo to hand-rear chicks for birds said: “Having spent long days working around the clock to hand raise these precious birds, it’s so incredible seeing them not only fully grown, but also now flying around Palmyra Atoll. Soon the whole flock will be out in their new forest home. It’s such an honour to be part of this journey to not only return sihek to the wild, but also to one day return them to the island of Guam.” 

The sihek made their maiden voyage from Wichita, Kansas to temporary aviaries on The Nature Conservancy preserve and research station at Cooper Island on August 28, 2024. Specialists have been caring for the palm-sized birds, ensuring that the sihek safely settled into their aviaries, acclimatized to their new homes, and received daily feedings.  

Professor John Ewen, from ZSL’s Institute of Zoology and Sihek Recovery Program Team Chair said: “This is a momentous day that has been decades in the making. Wildlife globally is under threat, and the success of seeing these birds fly in the wild once more highlights just how zoos, scientists and conservationists – working with governments and decision-makers – have the power to protect species and take huge steps in bringing them back from the very brink of extinction.” 

First listed under the Guam Endangered Species Act in 1982, the sihek was subsequently added to the U.S. Endangered Species List in 1984.  Endemic to the forests of Guam and culturally important to the CHamoru* people, the sihek have been extinct in the wild since 1988 due to predation by the invasive, brown tree snake. The Guam DOAG and AZA rescued 29 sihek and established a ex-situ-care program, which currently is composed of 127 adult sihek across 25 institutions, nationwide. 

Association of Zoos and Aquarium (AZA) partners contributing eggs or young chicks to this effort include the Brookfield Zoo, Cincinnati Zoo & Botanical Garden, Disney’s Animal Kingdom (Disney’s Animals, Science, and Environment), National Aviary, and Sedgwick County Zoo. Smithsonian’s National Zoo and Conservation Biology Institute (NZCBI) coordinated egg selection and transfer, and managed the care of the birds along with ZSL staff. 

The Sihek Recovery Program includes partners from the: U.S. Fish & Wildlife Service (USFWS), Guam Department of Agriculture’s Division of Aquatic & Wildlife Resources (DOAG), ZSL, The Nature Conservancy (TNC), Sedgwick County Zoo, AZA, and the International Union for the Conservation of Nature (IUCN). 

Scott Newland, President & CEO of Sedgwick County Zoo, added, “AZA partners have proudly maintained the Sihek population in human care since 1988. Without the dedication of our aviculturists and the support of zoos, this release would not have been possible. Our work with this species has provided us with valuable knowledge, allowing us to tailor this release to give the birds the best chance for success. For AZA, this release represents the culmination of nearly 40 years of collaboration, research, and dedication aimed at seeing the Sihek flying back on Guam one day.” 

“We are demonstrating that passion and partnership can make amazing things happen,” said Megan Laut, U.S. Fish and Wildlife Service recovery program manager. “The diverse skill set and contributions of each partner have led us to this historic milestone and will inform our efforts to grow the global population of sihek and take meaningful advances to return sihek to Guam.”  

Palmyra Atoll was selected as the inaugural site for sihek to be released to the wild because it is invasive predator-free and fully protected. Palmyra Atoll is a U.S. Fish and Wildlife Service National Wildlife Refuge and is further protected—out to 50 nautical miles—by the Pacific Remote Islands Marine National Monument, one of the largest swaths of ocean and islands protected under a single jurisdiction in the world.  The Nature Conservancy manages a preserve and research station at Palmyra on Cooper Island. These facilities enable globally significant ocean, coral reef and island research and restoration such as this sihek project. The atoll will provide the sihek a safe, wild home to thrive in and establish a breeding population, with the ultimate goal of one day returning the species to Guam once the threat from snakes is addressed.    

“Palmyra Atoll is an ideal location for rewilding these magnificent birds on their journey back to Guam,” says Alex Wegmann, TNC’s Lead Scientist for Island Resilience. “It is one of the healthiest land and ocean ecosystems on the planet, is free of invasive predators like rats, is carefully studied and monitored, and is fully protected as a national wildlife refuge and TNC preserve. Extensive research shows Palmyra’s forests are ideal for the sihek and that introducing it will have minimal effects on native wildlife there.” 

At this time, six of the nine sihek were deemed ready for release. The remaining three sihek will be released individually as each bird reaches milestones needed to survive in the wild. This approach provides necessary flexibility, as some birds may require more time to prepare for life in the wild. Sihek Recovery Program partners plan to continue supplementing the population annually, with a target of establishing ten sihek breeding pairs. 

This introduction of sihek to Palmyra will allow Sihek Recovery Program partners time to monitor and learn how sihek respond to returning to the wild. This initial release of sihek will help refine and tailor future releases and monitoring techniques, and provide an important step toward the goal of returning sihek to their native home on Guam.   

ZSL believes nature can recover, and that conservation is most effective when driven by science. With both COP16 and COP29 on the horizon putting a spotlight on nature, we call for science to guide all global decisions on environment and biodiversity and build a healthier future for wildlife, people and the planet. Find out more and support ZSL’s world-leading, collaborative science and conservation work at www.zsl.org