Whipsnade Zookeeper helps hand rear extinct in the wild chick

The Sihek Recovery Program is an international collaboration between wildlife experts across the world – including ZSL’s Whipsnade Zoo – who are working together to restore a wild population of this species, which is currently only found in human care.

The female chick hatched on 28 April at Sedgwick County Zoo in Kansas, US, and is being cared for around the clock by a team of specialists to ensure the precious youngster’s survival – including two keepers from ZSL’s conservation zoos, London and Whipsnade, who travelled to the US as part of the organisations wider initiative to recover extinct-in-the-wild species.

Known as sihek by the indigenous CHamoru* people, the species once flourished on the North Pacific island of Guam. However, the introduction of the brown tree snake to the island in the 1940s wiped out many native birds, bats and lizards.

The last wild sighting of sihek was in 1988 and the birds are now considered Extinct in the Wild by the IUCN. There are currently only 141 sihek left in the world, all under human care. Now the sihek Recovery Program is working to establish a temporary wild population on the island of Palmyra Atoll - where there are no invasive snakes or other predators such as rats - before their eventual return to Guam.

Claire McSweeney, a bird keeper from Whipsnade Zoo with years of expertise in rearing endangered birds, travelled to Sedgwick County Zoo to help ensure the tiny hatchling thrives. Claire said:

“This is my second year caring for sihek hatchlings at Sedgwick County Zoo as part of the Sihek Recovery Project,” she said.

“Along with my colleague from London Zoo, we’ve been caring for the chick around the clock, from feeding and weighing the bird to monitoring its health, sometimes for 12 hours at a time.

“As the numbers of siheks are so low, there’s a risk of poor fertility among the females. The fact that we already have one chick who is doing so well, is such a positive step for the recovery of the species.”

While the sihek chick is currently enjoying a nutritious diet of mice, in the forests of Palmyra Atoll the flock will have to learn to hunt and forage for everything from insects to geckos.

Claire said the team had also started to train the chick to associate its food with the sound of a whistle. The team on the ground will use a whistle sporadically to monitor the wild population.

“This will be important once the sihek are transported to Palmyra Atoll. The team on the ground can blow a whistle and then the birds will know where they can go if they need help finding food. It will also offer an opportunity for the team to continue monitoring the precious birds once they’re released into the wild. We want to make sure they have the strongest opportunity to survive and flourish.”

Yolonda Topasna, from the Guam Department of Agriculture’s Division of Aquatic and Wildlife Resources said: "We’re all thrilled that this year’s first chick has hatched and is doing so well. These beautiful birds haven’t sung in the forests of Guam for over 30 years, but this exciting moment brings us one step closer to the release of Guam sihek onto Palmyra Atoll - a pivotal step towards the eventual reintroduction of this stunning creature to Islan Guahan."

With more chicks due to hatch over the coming weeks, the collaborative Sihek Recovery Program hopes to release nine chicks onto the predator-free zone and fully protected island of Palmyra Atoll later this year. Here the birds will continue to be raised in aviaries at The Nature Conservancyʻs preserve at Palmyra Atoll until they are ready to be released into the wild across the atoll and into the U.S. Fish and Wildlife Service National Wildlife Refuge, making them the first wild population of sihek in almost 40 years. The releases will be repeated annually until 20 sihek successfully establish as breeding pairs. They will then be tracked and monitored, before hopefully raising the first wild-born sihek chicks since the 1980s.

Professor John Ewen, from ZSL’s Institute of Zoology and Sihek Recovery Program Team Chair said: “Conservation zoos have played a vital role in saving these birds from certain extinction through a recovery operation initiated in the 1980s with an ongoing breeding programme. Now, in a growing global partnership, we’re working towards the next exciting step of releasing sihek back into the wild, first on Palmyra Atoll where they will find a safe wild home to thrive in, but ultimately then to a snake-free Guam.”

John also underlined the complexity involved in re-establishing a wild sihek population: “Returning species to the wild is a long, carefully planned-out journey built upon global scientific expertise. When a species is as close to the edge of extinction as the sihek, low population numbers mean we often face challenges such as a lack of eggs and reduced fertility. As a result, only 1 of the 7 eggs that have made the journey to Sedgwick County Zoo so far has successfully hatched – highlighting not only how special this tiny chick is, but why it’s so vital that we continue to build large populations of Extinct in the Wild species under human care and work as quickly as possible to restore their wild numbers.

“We're hoping to release nine chicks on Palmyra Atoll later this year - but this all depends on what happens over the next few weeks.”

However, the team remains hopeful for the future of this colourful bird. John continued: "It’s still early days on the road to establishing a thriving wild population of sihek, but we know from other successes – such as the 2023 downlisting of the previously Extinct in the Wild scimitar horned oryx after the antelope’s reintroduction to Chad - that we can reverse the fate of the species on the very brink of extinction. Siheks deserve a chance to flourish in the wild once again – and it’s well worth taking our time to get it right.”

ZSL believes nature can recover, and that conservation is most effective when driven by science. 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 and support the restoration of these birds and other species by donating at www.zsl.org