College of Science

Species most likely to go extinct sooner were endemic to islands, lacked the ability to fly, had larger bodies and sharply angled wings, and occupied ecologically specific niches, according to research published this month.

While some of these findings mirror previous research on extinct birds, they are the first to correlate bird traits with the timing of extinctions, said lead author Kyle Kittelberger, a graduate student in the School of Biological Sciences.

“I’ve been very interested in extinctions and understanding the species that we’ve lost and trying to get a sense of how we can use the past to better inform the present and future,” said Kittelberger, who is completing his dissertation on how the bodies and wings of certain species of migratory songbirds have changed in response to climate change.

Connecting bird traits with species extinction

His team’s analysis tapped into BirdBase, a dataset of ecological traits for the world’s 11,600+ bird species compiled by U biology professor Çağan Şekercioğlu and the Biodiversity and Conservation Ecology Lab at the U. The team simultaneously analyzed a broad range of biogeographical, ecological and life history traits previously associated with extinction and extinction risk for bird species that have gone extinct as well as those that lack recent confirmed sightings and have therefore disappeared.

One in eight species is in peril

This timing coincides with the rise of scientific observation, resulting in a systematic documentation of plant and animal life. It is also the time when European exploration took off, leading to the disruption of ecosystems around the globe as a result of colonization and introduced species.

Today, 1,314 bird species are at risk of extinction, according to the IUCN Red List of Threatened Species, or about 12% of the total.

Many species, such as the ‘Akikiki (Oreomystis bairdi), endemic to the Hawaiian island of Kauai, are so rare that they are functionally extinct. Kittelberger photographed the pictured ‘Akikiki, also called Kauai’s creeper, in the Alaka‘i Wilderness Preserve in 2022, when it was believed around 70 or so remained in the wild; today, only one individual remains.

As with many other Hawaiian bird species, the main threat to the ’Akikiki comes in the form of introduced species, principally malaria-carrying mosquitoes and habitat-wrecking livestock, according to Hawaii’s Division of Forestry and Wildlife.