A gaggle of island giants
{ Posted on Friday, July 24, 2009
by Speculative Biologist
}
In future Atlantic isles, not present in Holocene Earth, there is a variety of large waterfowl like none ever seen before. In size, they are similar to an ostrich or even the extinct moa of New Zealand. The birds have small heads with long swan-like necks. Their bodies are large and fat and are held up by relatively short and stalky legs. The wings are nearly nonexistant, having become useless for these flightless giants.
Birth of an island chain
As millions of years in time pass, the world will constantly change geographically. Currently, the Pacific Ocean in shrinking due to the continuous westward movement of the American continents. As the Pacific shrinks, the Atlantic Ocean will spread. Tectonic forces in the Atlantic will likely produce a number of volcanic islands, possibly similar to the Galapagos and Hawaiian island chains present in the Holocene Pacific. Once the islands begin to jut out above the surface and the volcanic activity begins the slow, they will easily be colonized by a number of plant and animal species. Using Bermuda and the Azores as models, the islands would have a subtropical or temperate climate. The landscape would be dominated by broadleaf forest with plants like evergreens (cedars, oaks, etc.) and ferns (including tree-ferns such as palmettos). Once plants have established themselves, animals would begin colonizing the islands, especially migratory birds and insects, possibly bats as well. Eventually, after millenia of existence, species will evolve that are unique to this archipelago, possibly including flightless birds.
Giant waterfowl
This future giant is in no way a new development. There have been a number of occasions where waterfowl (birds of the order Anseriformes) have adapted to a flightless lifestyle and even have become gigantic in proportion. Hawaii has produced a number of such species in its history. The most notable would be the various species of moa-nalos, large herbivorous ducks with large heavy bills. These large folivores lived in the Hawaiian chain from about 3.6 million years ago to sometime after Polynesian colonization (but before European arrival). Hawaii was also home to a large Branta goose (the wood-walking goose or Branta hylobadistes) that apparently was moving towards a flightless lifestyle and was larger than the modern Nēnē (Branta sandvicensis). Neither the moa-nalos nor the wood-walking goose are anything in comparison to the group waterfowl-related titans, which lived in Australia only about 20,000 years ago (which means during the last ice age and after the human colonization of the Australian continent). The dromornithids were massive birds that could reach 3 meters in height and may have been voracious predators, scavengers, or opportunistic omnivores. With so many examples of waterfowl evolving into flightless giants, it isn't far-fetched to suggest that waterfowl could produce even more large forms.
The gander of ganders
The giant goose that has become adapted to the isles and lost its ability to fly is a descendant of the migratory Brent geese (although it may just as well evolve from the grey geese of the genus Anser, the Brent goose is simply used for this model). This massive goose has grown so large due to a lack of large mammalian predators, just like the moas and the elephant birds. The lack of predators is supplemented by a surplus of vegetation for food, provided by the fertile soil of the volcanic islands and the minimal amount of other species that could impede on the dietary requirement of such large birds. Their long necks also allow them to reach out and eat leaves far out of reach of most other ground birds that dwell the same territory. Island gigantism such as this has occurred many times in both mammals and birds during the Cenozoic.
Seeing as there is much risk of predation, adults of this great bird have highly decorative plumage. The head and neck are covered in a wonderful pattern of black, white, and blue. The bill is thick and large for ripping up leaves and other tough plant matter and is topped by a small disc-shaped crest similar to that of certain swans, but larger in proportion. In males the crest is larger and is a vibrant blue, while in females it is smaller and is a dull grey or black. The body is mostly greyish with a white underbelly. The wings are extremely tiny and are plain-colored with some black blotches. The goose's legs are very stubby and limit the creature to a slow waddle-like pace (there is no need to be a fast runner when there is nothing chasing you).
The titans of the Atlantic are gregarious and live in gaggles consisting of somehow related individuals. One dominant pair governs the entire gaggle and consists of an alpha male and alpha female. All are monogamous and typically have only one mating partner in their entire life. Eggs are laid on the ground in the underbrush. They are covered with soil and detritus to protect them from egg-eating carnivores. Once hatched, the young goslings are raised by both the male and female parent and are protected by the entire gaggle. Predatory birds and reptiles will sometimes attack and eat young goslings.
This concept is open for reuse and modification. Remember that any art on this blog is copyright to the respective owners and therefore cannot be claimed as your own.
Birth of an island chain
As millions of years in time pass, the world will constantly change geographically. Currently, the Pacific Ocean in shrinking due to the continuous westward movement of the American continents. As the Pacific shrinks, the Atlantic Ocean will spread. Tectonic forces in the Atlantic will likely produce a number of volcanic islands, possibly similar to the Galapagos and Hawaiian island chains present in the Holocene Pacific. Once the islands begin to jut out above the surface and the volcanic activity begins the slow, they will easily be colonized by a number of plant and animal species. Using Bermuda and the Azores as models, the islands would have a subtropical or temperate climate. The landscape would be dominated by broadleaf forest with plants like evergreens (cedars, oaks, etc.) and ferns (including tree-ferns such as palmettos). Once plants have established themselves, animals would begin colonizing the islands, especially migratory birds and insects, possibly bats as well. Eventually, after millenia of existence, species will evolve that are unique to this archipelago, possibly including flightless birds.
Giant waterfowl
This future giant is in no way a new development. There have been a number of occasions where waterfowl (birds of the order Anseriformes) have adapted to a flightless lifestyle and even have become gigantic in proportion. Hawaii has produced a number of such species in its history. The most notable would be the various species of moa-nalos, large herbivorous ducks with large heavy bills. These large folivores lived in the Hawaiian chain from about 3.6 million years ago to sometime after Polynesian colonization (but before European arrival). Hawaii was also home to a large Branta goose (the wood-walking goose or Branta hylobadistes) that apparently was moving towards a flightless lifestyle and was larger than the modern Nēnē (Branta sandvicensis). Neither the moa-nalos nor the wood-walking goose are anything in comparison to the group waterfowl-related titans, which lived in Australia only about 20,000 years ago (which means during the last ice age and after the human colonization of the Australian continent). The dromornithids were massive birds that could reach 3 meters in height and may have been voracious predators, scavengers, or opportunistic omnivores. With so many examples of waterfowl evolving into flightless giants, it isn't far-fetched to suggest that waterfowl could produce even more large forms.
The gander of ganders
The giant goose that has become adapted to the isles and lost its ability to fly is a descendant of the migratory Brent geese (although it may just as well evolve from the grey geese of the genus Anser, the Brent goose is simply used for this model). This massive goose has grown so large due to a lack of large mammalian predators, just like the moas and the elephant birds. The lack of predators is supplemented by a surplus of vegetation for food, provided by the fertile soil of the volcanic islands and the minimal amount of other species that could impede on the dietary requirement of such large birds. Their long necks also allow them to reach out and eat leaves far out of reach of most other ground birds that dwell the same territory. Island gigantism such as this has occurred many times in both mammals and birds during the Cenozoic.
Seeing as there is much risk of predation, adults of this great bird have highly decorative plumage. The head and neck are covered in a wonderful pattern of black, white, and blue. The bill is thick and large for ripping up leaves and other tough plant matter and is topped by a small disc-shaped crest similar to that of certain swans, but larger in proportion. In males the crest is larger and is a vibrant blue, while in females it is smaller and is a dull grey or black. The body is mostly greyish with a white underbelly. The wings are extremely tiny and are plain-colored with some black blotches. The goose's legs are very stubby and limit the creature to a slow waddle-like pace (there is no need to be a fast runner when there is nothing chasing you).
The titans of the Atlantic are gregarious and live in gaggles consisting of somehow related individuals. One dominant pair governs the entire gaggle and consists of an alpha male and alpha female. All are monogamous and typically have only one mating partner in their entire life. Eggs are laid on the ground in the underbrush. They are covered with soil and detritus to protect them from egg-eating carnivores. Once hatched, the young goslings are raised by both the male and female parent and are protected by the entire gaggle. Predatory birds and reptiles will sometimes attack and eat young goslings.
This concept is open for reuse and modification. Remember that any art on this blog is copyright to the respective owners and therefore cannot be claimed as your own.
A traveler of time and space, journeying the universe in search of intriguing ideas and scenarios for this blog. You can contact him at his deviantART profile: 
9 Response to "A gaggle of island giants"
Hey, remember the crane descendents I've proposed for the Evolutionary Continuum? Oh, those were the days. Considering that waterfowl and rails are the birds that will likely produce an huge amount of flightless islanders in the future, we might as well have some diversity.
As a side note, dromornids are no longer considered to be full time carnivores; Genyornis in particular was fully herbivorous according to egg shell studies, and given that they're part of a bird clade that is well known for herbivorous tendencies, it wouldn't be surprising if dromornids were mostly omnivores
Do note I said *may have been. But thanks for the heads-up anyway.
An interesting idea would be to see which species of migratory anseriformes migration routes would actually take them within the vicinity of these new islands (to an extent), and see who will land there. Perhaps some hawk or cathartid (I know a couple species do migrate) will land there, and end up either as a Haast Eagle wannabe or else a "ground hawk" (yes, I know it will be clumsy on the ground, but its on an island, where a clumsiness on the ground is not evolutionary fatal).
And don't forget that these islands are going to be in-between North America (particularly Florida), South/Central America, and Africa. Its a near-guarantee that the islands will be home to giant tortoises as well (descendents of ''Gopherus'' maybe?), or if not that some North American box turtle trying very hard to pretend it is a tortoise.
Actually I don't really see tortoises making that much distance by water. I would actually prefer the idea of Atlantic pseudo-tortoises, basically terrestrial forms of species like Box turtles or sliders.
Tortoises got to far-off places like the Galapagos and Maurititus by rafting. Obviously whatever tortoise taxon that would make it to the "Atlantis Islands" or whatever would be rather small and hardy, maybe a species that can hibernate or go without external resources for a long time, like the extant ''Gopherus''.
Barring tortoises, box turtles seem the most likely candidates. They are already taking the niches of the now extinct giant tortoises that once ran roughshod over North America in the Cenozoic, and seem to have a very bright future ahead of them (giant pseudotortoises of North America, no?).
Seems like a good idea. Now, the problem I see is tortoises and large ground birds cohabiting. Would they impede on each other's food sources?
Perhaps tortoises would adapt to more ground-feeding niches (think like the dome-backed tortoises of the Galapagos), and possibly be more grazer-like (hey, if geladas and swamphens can do it, why not tortoises), while the giant ground birds are the dominant browsers, using their long necks and powerful beaks to cut swaths through vegetation. Perhaps like in New Calidonia, some of these tortoises may get big and armored, taking the place of ankylosaurs, while birds remain the big browsers (like the New Calidonian Sylviornis).
Hah. I can just imagine an island populated by giant geese and neomeiolaniids. I doubt that large tortoises such as that would need heavy armor like that though. Perhaps it would evolve as more of a display mechanism rather than for defense.
Unless they were in danger of being preyed on by small island predators. Maybe a domestic cat or weasel that evolved into a giant fossa-like animal, or even terrestrial crocodilians.
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