Kuiornis indicator

By Ripley Cook

Etymology: The Demigod Kui’s Bird 

First Described By: Worthy et al., 2010 

Classification: Dinosauromorpha, Dinosauriformes, Dracohors, Dinosauria, Saurischia, Eusaurischia, Theropoda, Neotheropoda, Averostra, Tetanurae, Orionides, Avetheropoda, Coelurosauria, Tyrannoraptora, Maniraptoriformes, Maniraptora, Pennaraptora, Paraves, Eumaniraptora, Averaptora, Avialae, Euavialae, Avebrevicauda, Pygostylia, Ornithothoraces, Euornithes, Ornithuromorpha, Ornithurae, Neornithes, Neognathae, Neoaves, Australaves, Psittacopasserae, Passeriformes, Acanthisitti, Acanthisittidae 

Status: Extinct 

Time and Place: Between 19 and 16 million years ago, in the Burdigalian of the Miocene 

Kuiornis is from the Saint Bathans Fauna, a distinctive snapshot of the evolution of New Zealand’s unique birds – from the Bannockburn Formation of the South Island of New Zealand 

Physical Description: Kuiornis is known from limb elements, so we don’t know much about it, but it seems to have been only a little smaller than the living Rifleman, its closest relative – so it was probably around 7 centimeters long. It would have looked similar to the living Rifleman as well – a round bird, with a distinctively thin tail, and a small head with a triangular beak. As for differences from living New Zealand Wrens, it had differently formed and more compact legs. Beyond this, it’s difficult to say more about the specific appearance of Kuiornis; it probably would have been green and brown in color, like its living relatives. 

Diet: Without fossil evidence of the beak, we have to assume that Kuiornis was an omnivore; given that New Zealand Wrens today favor invertebrates but still eat other forms of food, this is not an unreasonable assumption. 

Behavior: Kuiornis would have been very skittish like modern New Zealand Wrens, flitting back and forth between the shrubs and vegetation in its habitat. It would have probably been only moderately social, like living New Zealand Wrens, and making high pitched, non-musical calls. Kuiornis would then spend most of its time foraging for food. When not doing that, it would have taken care of its young, building nests out of grass and in secluded spaces. It is difficult to say much about its breeding behavior – or behavior in general – however, since very little is known from this dinosaur. 

Ecosystem: At the end of the Paleogene, New Zealand flooded. This completely erased the previous ecosystem, killing most things that had been on the island before that point. Afterwards, the only things that were able to colonize the space were creatures that floated over, and creatures that could fly. This included lizards and snakes and other reptiles, bats, and most notably of all – birds. New Zealand had one of the most unique avifaunas of all time, with many birds evolving to fill roles that mammals took in other locations – things like the moas, the large birds of prey, the adzebills, and living forms like the New Zealand Parrots that are like avian rodents and rabbits. The Saint Bathans Fauna is a snapshot of that initial colonization, showing how these unique birds began to diversify after New Zealand reemerged, in a lush lake enviroment. Kuiornis is just one part of that – showing the origin of the weird New Zealand Wrens. There was also the early Kiwi Proapteryx, the small Manuherikia ducks, the stiff-tailed Dunstanneta, the shelduck Miotadorna, the goose Cereopsis, the wood duck Matanas, the weird pigeon Rupephaps, the early Adzebill Aptornis proasciarostratus, the flightless rails Priscaweka and Litorallus, the swimming flamingo Palaelodus, the herons Matuku and Pikaihao, the bittern Pikaihao, the New Zealand Parrot Nelepsittacus, and potential eagles and hawks. There were also many geckos, skinks, crocodilians, turtles, and tuatara present as well. Weirdly enough, there was a mammal other than bats – but that mammal is what we would call a Mystery. 

Other: Kuiornis has been extensively studied in phylogenetic analyses, and these analyses consistently recover Kuiornis as a New Zealand Wren, so it is an important find in understanding how this unique group of little dinosaurs evolved in such an isolated environment as New Zealand. Interestingly enough, it consistently comes out as very much nested in the group, extremely closely related to the Rifleman. This indicates that Kuiornis is not a decent model for the ancestor of the New Zealand Wrens, and also that advanced members of this group were present as recent as the mid-Neogene period. 

~ By Meig Dickson

Sources under the Cut 

Acanthisitta chloris

By Francesco Veronesi, CC BY-SA 2.0

Etymology: Thronbill-Nuthach

First Described By: Sparman, 1787

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, Inopinaves, Telluraves, Australaves, Eufalconimorphae, Psittacopasserae, Passeriformes, Acanthisitt, Acanthisittidae

Status: Extant, Least Concern

Time and Place: Since 126,000 years ago, in the Tarantian of the Pleistocene through today 

The Rifleman, or Tītipounamu, is known only from New Zealand 

Physical Description: Tītipounamu are very small, very round, perching birds, only reaching about 7 to 9 centimeters in total body length (that’s barely over 3 inches!) These birds are olive in color, with green undertones to the feathers. Their wings and tails are brown, and their backs also have brown spotting. Their necks are white, and they have yellowish bellies and rumps. The bills of Tītipounamu are moderate in length, and extremely pointed. The males are greener than the females, and the juveniles resemble the females before sexual maturity.

Diet: Tītipounamu feed primarily on insects, especially beetles, flies, and months, though they eat any sort of land arthropod generally. 

By Lake Sylvan, CC BY-SA 2.0

Behavior: Tītipounamu forage in small groups and pairs in the forest, picking up food scraps near human camps and searching for invertebrates in tree trunks, branches, twigs, and leaves. They rarely spend time on the ground and are very restless while they forage, always ready to fly away at the slightest hint of danger. They flit back and forth between trees and shrubs, in search of food. It will start close to the ground and climb up the trunk, spiraling around it to look for food. They make sharp, fast, simple “zipt-zipt-zipt” calls that are actually ultrasonic!

Tītipounamu breed from August through February. They form long-term, monogamous pair bonds, which usually have two broods per breeding season. They have helpers, usually unpaired adult males for the first brood of the season, and then the first brood with the second brood. The parents work together to build the nest, making a dome-shaped nest out of sticks and gross with a side entrance tunnel. The nests are lined with dead leaves, moss, spider webs, and feathers. They’re usually placed in tree trunks or on branches, and they do use human nest boxes. The broods are two to five eggs that are incubated for three weeks by both parents. Both parents then help to feed the chicks for about a month. The fledged young are then fully independent at six weeks. Most young manage to fledge, though these numbers decrease in the second brood. Tītipounamu do not migrate, though they will move a little to look for food; the juveniles disperse a bit after leaving the family. 

By Brian Ralphs, CC BY 2.0

Ecosystem: Tītipounamu live in beech and bine forests and associated scrub, especially very dense older ones with large numbers of understory plants. They are often found in remnant patches of native vegetation in cleared areas, and they can also be found in more human maintained habitats. They’re usually found in the uplands. These birds are often preyed upon by mammals such as stoats and introduced cats.

Other: Tītipounamu are not threatened with extinction, and they are in fact quite common. This is good, because they’re among some of the most unique birds – New Zealand Wrens, such as Tītipounamu, are the earliest-diverging group of perching birds, equally related to all other members of Passeriformes. There aren’t many living New Zealand Wren species today, making each one a unique window into a distinctive side branch of Passeriform evolution.

~ By Meig Dickson

Sources under the Cut