The Great Oʻahu crake (Porzana ralphorum) is an extinct species of flightless rail that was endemic to the island of Oʻahu in the Hawaiian Islands. It is known exclusively from subfossil bone remains discovered in archaeological and paleontological sites on the island.
Etymology and Discovery
The species was formally described in 1997 by American paleontologists Storrs L. Olson and Helen F. James. The specific epithet ralphorum honors Ralph and Mary Mae Wetmore, who were significant benefactors and supporters of ornithological research. The common name "Great Oʻahu crake" distinguishes it from another extinct crake found on Oʻahu, the Oʻahu crake (Porzana ziegleri), which was significantly smaller.
Description and Biology
Like many island rails, the Great Oʻahu crake is believed to have been flightless or had significantly reduced flight capabilities, a common evolutionary adaptation in environments without terrestrial predators. Its skeletal structure indicates a relatively robust bird, larger than most other Porzana crakes. While its plumage is unknown, it likely shared characteristics with other members of its genus, which are typically secretive, ground-dwelling birds.
Its diet would have likely consisted of invertebrates, seeds, and other plant material found in its terrestrial habitat, which would have encompassed the diverse ecosystems of ancient Oʻahu, from coastal lowlands to montane forests.
Habitat
The Great Oʻahu crake inhabited Oʻahu prior to widespread human settlement. Its subfossil remains have been found in various locations, suggesting it was once widely distributed across the island's landscape.
Extinction
The extinction of the Great Oʻahu crake, like many other endemic Hawaiian birds, is directly linked to the arrival of Polynesian settlers approximately 800-1,000 years ago, and subsequently, European contact. The primary drivers of its demise were:
- Habitat destruction: Conversion of native forests for agriculture and and human settlements.
- Introduced predators: Non-native animals such as the [[Polynesian rat]] (Rattus exulans), dogs (Canis familiaris), and pigs (Sus scrofa) preyed upon the flightless birds and their eggs.
- Competition: Introduced species may have competed for food resources.
The Great Oʻahu crake is one of numerous examples of the unique biodiversity that was lost from the Hawaiian Islands following human colonization.