Bird species lost from wild for almost 40 years lays first eggs on new island home

Sihek – an endangered bird recently returned to the wild – have laid eggs on their new Pacific island home for the first time, making them the first wild eggs for the species in almost 40 years.   

Nine young Sihek – also known as Guam kingfishers – hand-reared by zookeepers, were released at The Nature Conservancy’s (TNC’s) Palmyra Atoll Preserve in September 2024 by the Sihek Recovery Program, a global collaboration of conservationists – including ZSL – dedicated to rewilding these magnificent, colorful birds.  

The team behind the project are now celebrating as the eggs mark how the birds – reared by zookeepers including from ZSL’s Whipsnade and London Zoos – have flourished since their arrival to the Pacific Atoll, located about 1,000 miles south of Honolulu, Hawaiʻi. 

Returning Sihek to the wild

After their remarkable release last autumn, the four female and five male birds quickly explored their new home, learning how to forage and hunt new prey within the tropical forest. Four pairs have since established territories, built nests, and laid eggs, marking the first time the species has bred in the wild since its extinction from their native island of Guam in the 1980s. 

Professor John Ewen, from ZSL’s Institute of Zoology and Sihek Recovery Program Team Chair said: “Many of us spent this Easter weekend out searching high and low for eggs of a different variety – and while they might not be as shiny or brightly coloured, these tiny, unassuming-looking eggs are far more exciting and precious than any of their chocolate counterparts. They are a remarkable milestone for the decades-long mission to rescue the Sihek from the edge of extinction, and this moment for celebration is a real testament to all the dedicated work from everyone working around the clock to protect and recover this incredible bird.”

Dr. Caitlin Andrews, Bird Conservation Scientist with ZSL and TNC added: “We’re delighted that all nine of the birds are not only surviving on Palmyra Atoll, they’re already starting the next stage of their journey as we work to reestablish a thriving and fully self-sustaining Sihek population in the wild. It’s taken years of planning to get to this point, and it’s wonderful seeing their instincts kick in as they’ve been catching geckos and spiders and excavating nests. Their strength provides hope they will one day be back on Guam.” 

With the mated pairs less than a year old, this is their first time incubating and caring for eggs, meaning it’s likely it will take a few rounds of egg laying for the birds to hone their skills and hatch chicks. Nonetheless, these eggs demonstrate both the tremendous resilience of these remarkable birds and the power of conservation to create a second chance for species on the brink of extinction.  

Why are sihek under threat?

Sihek, as the birds are known by the indigenous CHamoru* people of Guam, also known as Guåhan, were decimated when the brown treesnake was accidentally introduced to the island in the 1940s. The last wild sihek was seen in 1988. But as the population crashed, Guam biologists brought 29 sihek under human care, starting a conservation breeding program in Association of Zoos and Aquariums (AZA)-accredited zoos across the United States (US). 

Palmyra Atoll was selected as the home for the first wild Sihek in almost 40 years because it is predator-free and fully protected. TNC’s Palmyra Preserve is encompassed by the U.S. Fish and Wildlife Service’s Palmyra Atoll National Wildlife Refuge (out to 12 nautical miles) and by the Pacific Islands Heritage Marine National Monument (out to 50 nautical miles), one of the largest swaths of ocean and islands protected in the world. Protected regions like Palmyra Atoll are essential to protecting biodiversity as wildlife globally continues to face threats such as habitat loss and climate change.    

Charlotte James, one of the London Zoo bird keepers who travelled to Sedgwick County Zoo to hand-rear the released birds said: "After many long days last year looking after these birds when they were just tiny eggs and chicks, it's so rewarding to see them beginning their journey towards raising their own chicks in the forests of Palmyra Atoll. It's hard not to feel like a proud parent seeing them out there thriving and making history - and an honour to be part of the ongoing mission to bring sihek back from the brink of extinction."  

Yolonda Topasña, Guam Department of Agriculture Division of Aquatic and Wildlife Resources (DAWR) Program Coordinator said: “The Guahan Sihek continue to etch their story upon us, marking milestones with Tutuhan again at the forefront! Tutuhan was the first hatchling last year and now is the first to produce eggs. Her name means beginning and she showed signs of strength from the beginning, wanting to feed herself before being old enough to do so. Tutuhan challenged another female for Hinanao’s partnership and won! Now our pair take turns watching over their precious eggs.

“The connection I feel with Tutuhan is a kinship I hope for all to feel. I envision our people, the CHamoru, those who dwell in our beloved Guahan and those scattered across the vast oceans, to feel the same stirring of ancestral pride. A dear friend in Washington, but whose roots run deep on Guahan, shared a memory, a vision of sihek soaring freely over their lancho (farm) in Dededo, in the mid-1970s. My friends’ father warned the family to leave sihek alone and they respected and obeyed. These are the stories that bind us, the whispers of our past that illuminate our present. These conversations are what will bring us all together to celebrate the lives of the sihek thriving on Palmyra Atoll and in turn, will help us all take pride in our culture and heritage.”

What are the next steps for Sihek conservation?

Plans are underway for more young Sihek to be released at Palmyra Atoll this summer. Egg laying season is underway at participating AZA-accredited institutions across the US. As they grow to maturity, these chicks will also journey to Palmyra, with the ultimate goal of establishing ten breeding pairs there. The wild Sihek at Palmyra Atoll will pave the way for a growing, wild Sihek population for the first time in decades.  

_{*The CHamoru name is spelt with a capitalised H. Sihek is capitalised in CHamoru}