#apteribis

[alphynix]

Extinct Hawaiian ibis with strangely small eyes suggests a shift to nocturnal life

Islands are famous for producing some of the world's strangest creatures, and now a new international study shows that the evolution of bird

[cellulosaurus]

I love birds with a crappy eyesight, little contrarians

[a-dinosaur-a-day]

Apteribis

By Scott Reid 

Etymology: Wingless Ibis

First Described By: Olson & Wetmore, 1976

Classification: Dinosauromorpha, Dinosauriformes, Dracohors, Dinosauria, Saurischia, Eusaurischia, Theropoda, Neotheropoda, Averostra, Tetanurae, Orionides, Avetheropoda, Coelurosauria, Tyrannoraptora, Maniraptoromorpha, Maniraptoriformes, Maniraptora, Pennaraptora, Paraves, Eumaniraptora, Averaptora, Avialae, Euavialae, Avebrevicauda, Pygostaylia, Ornithothoraces, Euornithes, Ornithuromorpha, Ornithurae, Neornithes, Neognathae, Neoaves, Aequorlitornithes, Ardeae, Aequornithes, Pelecaniformes, Threskiornithidae, Threskiornithinae

Referred Species: A. glenos (Molokai Flightless Ibis), A. brevis (Maui Flightless Ibis)

Status: Extinct

Time and Place: Between 200,000 years ago until sometime in the past 1000 years, from the Chibanian of the Pleistocene through the Holocene   

Apteribis is known from the islands of Maui, Lanai, and Molokai 

Physical Description: Apteribis looked, in a lot of ways, like your typical Ibis - it had a very long bill and skinny legs. Beyond that, though, it looked very different - it was more squat, for one, and it had a large round body. It also basically didn’t have any wings. This gave it, in a lot of ways, the appearance of a Kiwi, but it was an Ibis! We do have feathers from this animal that show it was brown in color, some darker brown and other feathers lighter brown of course but still overall brown - helping to add to that appearance like a Kiwi. And, like the living Kiwi, it was flightless.

Diet: There is nothing to suggest that Apteribis wasn’t like other Ibises, feeding mainly on invertebrates.

Behavior: Even though Apteribis was flightless, it still had hooklets in its feathers - usually used to provide structure in flight, for Apteribis they would have provided strength against stress in the wind and water. As such, Apteribis probably still contended with fairly perilous environments, probing through the waves or wading in strong wind to find food. It also probably spent a good amount of time looking for food in the litter of the forest floor, being associated strongly with the rainforests of Hawai’i. It would have used that long beak for probing, and its still skinny legs to carefully wade through whatever it was walking across. Beyond that, the rest of its behavior is uncertain - without flight, it wouldn’t have moved around much; and it probably would have taken care of its young. 

By José Carlos Cortés

Ecosystem: Hawai’i during the Ice Age was similar to Hawai’i today, just with some more arid conditions and different wildlife in general. Much like New Zealand, Hawai’i featured many kinds of unique birds, including Apteribis. There were also the Giant Hawaii Goose, a giant finch called the Giant Amakihi, the Giant Maui Crake, the High-Billed Crow, the Kaua’i Mole Duck, the Moa-Nalo, The Nēnē-nui, Stilt-Owls, and so many more.  

Other: Apteribis did get quite big, but overall it wasn’t an example of island gigantism, just island flightlessness.

Species Differences: A. glenos lived primarily on the island of Molokai, while A. brevis was found more on Maui.

~ By Meig Dickson

Sources Under the Cut 

Dove, C. J., S. L. Olson. 2011. Fossil Feathers from the Hawaiian Flightless Ibis (Apteribis sp.): Plumage Coloration and Systematics of a Prehistorically Extinct Bird. Journal of Paleontology 85 (5): 892 - 897.

Godino, F.M.J. (2011). "Maui Upland Apteribis". The Extinction Website. Retrieved 2011-01-07.

Olson, Storrs; James, Helen (1991). "Descriptions of Thirty-Two New Species of Birds from the Hawaiian Islands Part I. Non-Passeriformes". Ornithological Monographs. 7.

[alphynix]

Island Weirdness #42 — Tall Owls & Short Ibises

The complete lack of land mammals on the Hawaiian islands left the terrestrial predator niches available to birds — and it was owls who ended up taking advantage of that role in the ecosystem.

The Grallistrix owls were found on Kauaʻi, Oʻahu, Molokaʻi, and Maui, with each island having its own endemic species. They were a type of true owl, probably descended from a species of Strix, and developed especially long legs that led to their nickname of "stilt-owls".

The Molokaʻi stilt-owl (Grallistrix geleches) was the largest of the four known species, about 60cm tall (2'). Although it had proportionally short wings it was still capable of flying, and probably specialized in stalking and ambushing smaller birds like Hawaiian honeycreepers in the dense forests.

(These owls were also the inspiration for the pokémon Decidueye!)

Meanwhile the forest floor insectivore niche was occupied by Talpanas on Kauaʻi, but on the other main islands a different type of bird took up the same role.

Apteribis was an ibis closely related to the modern white ibis and scarlet ibis, with three different species found on the islands of Maui, Molokaʻi, and Lānaʻi.

The Moloka'i flightless ibis (Apteribis glenos) was a typical example of the genus, about 50cm long (1'8"). It was flightless, with reduced wings, and had unusually short stocky legs that gave it proportions much more like a kiwi than an ibis. And it probably lived very much like a kiwi, too, probing around in the forest litter with its beak searching for snails and other invertebrates.

We even have an idea of the coloration of these birds, thanks to subfossil remains with preserved feathers. They seem to have been brown and beige, similar to the juvenile plumage of their close relatives.

The arrival of humans at least 1000 years ago would have unfortunately been devastating to both the stilt-owls and the flightless ibises. The combination of hunting, habitat destruction, and invasive dogs, pigs, and rats attacking them and their ground-based nests probably drove them all into extinction very quickly.