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Diversification in Isolation

Helen James and Storrs Olson
Ancient Raptors and Rails

Helen James’ and Storrs Olson’s research on over 50 fossilized Hawaiian bird species has provided crucial insights into their evolution, the impact of human colonization, and has shaped conservation strategies to protect and restore native bird populations.

A long metallic and mesh fence running along a dirt path with lush greenery on both sides, under a clear blue sky with a view of water in the distance.
Three hikers with backpacks walk along a fenced trail up a green, tree-lined hill under a clear blue sky.

Images: Predator-proof fences on Hawaii’s isolated islands are vital for conserving native wildlife. These barriers, as seen in the steep terrain of Kauaʻi and other islands, prevent invasive species such as rats, cats, and mongoose from entering and disrupting the delicate ecosystems. By creating safe havens for native plants and animals, these fences play a crucial role in maintaining the unique biodiversity of Hawaii, which has evolved in isolation over millions of years. Conservation efforts like these are essential for preserving Hawaii’s natural heritage.

Diversification in Isolation

Key Takeaways

Pioneering Research.

Helen James and Storrs Olson significantly advanced our understanding of Hawaiian bird evolution by uncovering over 50 fossilized species, including previously unknown raptors, rails, and flightless waterfowl.

Evolutionary Insights.

Their work on the evolutionary history and adaptive radiations of these birds provides critical insights into how they evolved in response to Hawaiʻi’s unique environments.

Impact of Human Colonization.

Their research highlights the significant impact of human colonization on Hawaiian bird populations, documenting patterns of extinction following human arrival.

Shaping Conservation Strategies.

The detailed records and reconstructions by James and Olson have been instrumental in developing conservation strategies to protect and restore remaining native bird species and their habitats.

Helen James and Storrs Olson

It’s difficult to overstate the importance of the contributions made by avian paleontologists Helen James and Storrs Olson to our understanding of Hawaiian bird evolution. Through their extensive research and description of over 50 fossilized Hawaiian birds, they have uncovered a rich diversity of extinct avifauna, including previously unknown species of raptors, rails, and flightless waterfowl, like the moanalo. By reconstructing the evolutionary history and adaptive radiations of these species, they have provided critical insights into how these birds evolved in response to the unique environments of the Hawaiian Islands. Their research has also highlighted the significant impact of human colonization on these avian populations, documenting the patterns of extinction that followed human arrival. The detailed records and reconstructions by James and Olson have been instrumental in shaping conservation strategies aimed at protecting the remaining native bird species and restoring their habitats.

Their work involved meticulous examination of fossil remains and geologic evidence to reconstruct the evolutionary history and distribution patterns of Hawaiian birds. By analyzing bones, feathers, and other artifacts found in archaeological sites and natural deposits across the islands, James and Olson pieced together a narrative of how these birds lived, adapted, and ultimately disappeared due to human activities and environmental changes. Their research not only deepened our knowledge of Hawaiian biodiversity but also underscored the urgency of conservation efforts to protect the islands’ remaining endemic species from a similar fate.

Helen James is a research zoologist and curator of birds at the Smithsonian’s National Museum of Natural History. She has worked since the 1970’s to collect Hawaiian fossil birds in conjunction with Bishop Museum, where she is a research affiliate. In this video, she discusses how specimens from the fossil record are used in her research.

A person wearing a headlamp examines and organizes bones and artifacts in a plastic container.
Pioneering Research.
Helen James
Dr. Helen James collecting fossils of the giant Hawaiʻi goose (Branta rhuax) from a dry lava tube on the Big Island.
Pioneering Research.
A person in glasses and a casual shirt is kneeling outdoors while holding a wooden tray filled with soil or small items.
Evolutionary Insights.
Storrs Olson
Storrs Olson (1944–-2021). Storrs Olson, who spent his career at the Smithsonian’s National Museum of Natural History, was a systematist, anatomist, and curator of birds from 1975 to 2010.
Evolutionary Insights.
Helen James is a research zoologist and curator of birds at the Smithsonian’s National Museum of Natural History. She has worked since the 1970’s to collect Hawaiian fossil birds in conjunction with Bishop Museum, where she is a research affiliate. In this video, she discusses how the fossil record informs our understanding of when and how birds went extinct in Hawaiʻi.

Ancient Raptors and Rails

Today, the only native birds of prey in the Islands are the pueo (Asio flammeus sandwichensis), which occurs throughout the archipelago, and the ʻio (Buteo solitarius), which only occurs on Hawaiʻi Island. However, the fossil record has revealed a much more diverse assemblage of birds of prey in the Islands, particularly on Oʻahu. From fossils collected at both Pleistocene and Holocene sites, we know that Oʻahu was home to an eagle (Haliaeetus albicilla ssp.), a now-extinct species of hawk (Buteo sp.), a harrier (Circus dossenus), and a long-legged owl (Grallistrix orion). These fossils have provided evidence of once-thriving apex predators, illustrating the complexity of prehistoric food webs and the role of large birds of prey in the Islands’ ecosystems.

Similarly, the remains of at least six extinct flightless rails were found in the Islands’ fossil record. These rails exhibited significant morphological changes, such as reduced wings and robust legs, allowing them to thrive in dense vegetation. However, their inability to fly made them particularly vulnerable to predation and habitat destruction.

A bird with gray and orange plumage holds a red bird in its talons while perched on a tree branch in a lush forested area.
Hawaiian harrier
Extinct Hawaiian harrier (Circus dossenus) with a freshly-killed ʻiʻiwi (Vestiaria coccinea).
Painting by Julian Hume.
Illustration of four bird species perched on white rocks. From left to right: a small bird with blue-grey wings and orange chest, a large brown bird, a small bird with brown wings, and a light grey owl.
Clockwise from top: An extinct eagle (Haliaeetus albicilla ssp.), a now-extinct species of hawk (Buteo sp.), a long-legged owl (Grallistrix orion), and a harrier (Circus dossenus).
Painting by Julian Hume.
An illustration of a bird with green legs walking under a larger bird's tail in a forested area, with other birds visible in the background.
Molokaʻi rail
The Molokaʻi rail (Zapornia menehune) is the smallest species of rail, living or extinct, ever discovered. The species name, menehune, refers to the mythological race of leprechaun-like people in Hawaiian tradition who are said to live in the deep forests and hidden valleys.
Painting by Julian Hume.
Extinct Birds

Final Takeaways

Extensive Fossil Discoveries.

Helen James and Storrs Olson uncovered over 50 fossilized Hawaiian bird species, including unknown raptors, rails, and flightless waterfowl.

Evolutionary Understanding.

Their research provided critical insights into the evolutionary history and adaptive radiations of Hawaiian birds.

Human Impact.

They documented the significant impact of human colonization on Hawaiian bird populations, highlighting patterns of extinction.

Conservation Influence.

Their work has been instrumental in shaping conservation strategies to protect and restore native Hawaiian bird species and their habitats.
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