Biologists Celebrate as Extremely Rare Guam Kingfishers Nest for the First Time in Nearly 40 Years

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The vividly hued birds have been extinct in the wild since 1988, following the invasion of the brown tree snake in their native Guam. However, they are beginning to thrive once more on Palmyra Atoll.

A bird species that has been absent from its natural habitat for nearly four decades has found a new home in the Pacific Ocean, and it is reports of successful breeding that are raising hopes for its revival. The Guam kingfisher (Todiramphus cinnamominus), also known as “sihek,” has begun to lay eggs on Palmyra Atoll, supported by the dedicated efforts of conservationists.

Confident signs of adaptation have emerged on Palmyra Atoll, a secluded collection of 26 islets located approximately in the middle of the distances between Hawaii and American Samoa. Biologists exhibited cautious optimism after discovering the first eggs in a nest around 12 feet above ground on March 31.

The Guam kingfisher, revered as the “sihek” among the Indigenous CHamoru people, is a striking bird with a robust beak. Males display a blend of cinnamon-brown plumage with striking teal wings and tails, while females exhibit lighter breast feathers.

Renowned for their hunting prowess, sihek are adept at perching quietly before diving to catch their preferred meals, which include skinks, geckos, spiders, beetles, and land crabs. These birds exhibit intense territorial behavior, vigorously defending their established homes.

Historically, sihek populations thrived in Guam until the invasive brown tree snake drastically impacted the ecosystem, leading to the extinction of this species in the wild by 1988. Fortunately, prior to their disappearance, conservationists managed to rescue 28 sihek to cultivate a captive breeding population, ensuring the survival of the species.

In a significant step towards restoration, a group of nine Guam kingfishers—five males and four females—was released on Palmyra Atoll last September after being raised in various zoos across the United States. Following their acclimatization period, they were fitted with radio trackers before being freed into their new environment.

Geographically, Palmyra Atoll is situated about 3,600 miles from Guam; however, it was chosen as a release site due to its ecological protection status as part of the U.S. Fish and Wildlife Service’s National Wildlife Refuge and the Pacific Remote Islands Marine National Monument. The atoll’s ecosystem has been cleared of invasive species like rats that would threaten the new avian inhabitants.

These nine kingfishers were brought together to the Sedgwick County Zoo in Kansas for care and rearing before undertaking their extensive 4,500-mile journey to their new home in the remote research station on Palmyra Atoll. The recent sighting of eggs in the wild marks a monumental achievement in the ongoing efforts to reestablish this species.

“Their release has opened a new chapter for this critically endangered bird,” remarks Martin Kastner, a biologist from the Nature Conservancy involved in the reintroduction. “Now they are foraging, nesting, and reproducing independently. This is a major milestone for us.”

The discovery of the eggs came after a routine check by biologists on March 31, when they found the first nest empty but soon located another nest containing an egg. An inspection using an endoscope revealed the egg, which had not been seen in the wild for nearly four decades—signifying a breakthrough for the species.

Kastner expressed the emotional weight of the moment when the egg was found, reflecting on the years of effort by dedicated individuals in conservation—making the discovery a profound source of joy and hope. A second egg was identified just five days later, with the expectation of further nesting activity.

Such findings weren’t wholly unexpected; Kastner had just recently captured the first known instances of sihek mating in the wild since the species’ extinction. The team will monitor the progress of the eggs, as the new parents may require several laying attempts before chicks successfully hatch.

In captivity, Guam kingfishers generally lay fertile eggs after reaching about 11 months of age, while the Palmyra Atoll residents are still only around 9 months old.

In the long run, conservationists aim to establish a sustainable population of up to 30 breeding pairs on Palmyra Atoll, with plans to continue sending hand-reared chicks from various zoos. Another batch of nine sihek is expected to arrive this summer for eventual release.

The overarching goal remains to eventually reintroduce the species to Guam once the invasive brown tree snake situation is resolved. Kastner stated, “The primary focus must be on bringing them back home to Guam,” emphasizing that this remains the ultimate objective of the project.

As researchers celebrate this milestone in egg-laying, they take the opportunity to reflect on the conservation efforts that have led to partial restoration of the sihek. Kastner concludes, “This signifies that species can be revived with sufficient time and dedicated effort. The success we’ve seen here is a testament to the unwavering commitment of those who supported their capture for conservation.”

Source
www.smithsonianmag.com