There’s more to Hawaii than Jimmy Buffett (okay, I admit – I’m a Parrothead!), Elvis, surfing or  even Disney’s adorable and naughty alien Stitch. Even more so if you love earth sciences like us at Twilight Beasts. Hawaii is literally a hot spot for seeing hot fiery lava erupt like rivers of thick custard. What makes Hawaii a geologists dream is what lies beneath: it sits on top of a ‘hotspot’ – an area of the earth’s crust which produces considerable tectonic activity, even though there are no plate boundaries nearby. Geologists think that an enormous plume of hot, molten lava from deep within the Earth has floated up and pushed itself out at this location. As the Pacific Plate has been moving slowly for untold millennia in a north-westerly direction, right across the ‘hotspot’ there are older, now dormant Islands: evidence that the tectonic plate moved, slowly, over this massive hot magma balloon. It gets more complicated because it has been active for several million years, so there must be some ‘fresh’ molten rock being fed in to the plume. As it is today, the hotspot shows no signs of slowing, demonstrated by the spectacularly magnificent lava flows Hawaii regularly sees.

The never-ending magma being pushed out from the belly of the Earth. This diagram illustrates the awesome plume under the crust, as the plate above slowly moves over it. (Image  by Joel E. Robinson, USGS. From here.)

Studding the Pacific Ocean like a chain of fiery garnets, the Hawaiian Islands remained uncolonised by humans for most of prehistory – although who knows what new and exciting evidence will be found at some random excavation? That’s certainly why I do what I do! As a result of that splendid isolation – over 3800 km from the American coastline – the islands became home to species which cannot be seen, or matched, anywhere else in the world. Remember that island life does funny things to living, breathing creatures, making flora and fauna adapt to a specific ecosystem. I could tell you about fiendishly cute bird-eating owls, adorable mole-ducks – but they’ll all be for another time. This story is about the Giant Hawaiian Duck, the Moa-Nalo.

Their name in many ways reflects the sense of island isolation and also their extinction – Moa-Nalo means ‘ lost fowl’ in Hawaiian.  We know of four species; Kauai island’s Chelychelynechen quassus, Maui island’s Ptaiochen pau and Thambetochen chauliodous (though it was found on some other islands too), and Thambetochen xanion from Oahu. The exciting field of DNA research suggests the Moa Nalo were closely related to today’s little dabbling ducks who are members of the Anas genus. That being said, these were not little pond ducklings you’d be feeding peas or cracked corn to on a Sunday walk. These birds weighed in at around 16.5kg, with the muscular body of a large swan, although they were flightless. Their flightlessness initially led to them being classified as a variety of goose. However, one little bone from Moa Nalo that makes a duck quack like a duck and not sing like a lark (the fossilised syringeal bullae) allowed palaeontologists realise they were dealing with a duck which may very well have strayed from a different region of the Pacific a long, long time ago. A very large, very unique duck.

They certainly looked strange compared to our understanding of what a duck should look like. The weird Chelychelynechen quassus had  a stubby little beak which some feel looks more like a turtle’s snapper (the Latin name actually means ‘turtle jawed broken goose’), while the other genera had little serrated teeth-like edges to their beaks, sometimes called pseudoteeth (not true teeth, just teeth-like growths from their beaks).  That turtle beak and those little serrations were for a good reason.  Those ‘teeth’ were needed to chew through much coarser material than pondweed!

The very cute looking giant duck, as big as a swan, with the odd shaped ‘turtle’ beak. (Reconstruction by Carl Buell. Image from here)

Fossil poo is a wonderful thing. Coprolites (fossilised poo) can tell us a huge amount about the food consumed by any creature, and what ailments they may have been prone to. Studies of the Giant Hawaiian Duck poo have indicated the vegetation they ate was often coarse and prickly, including Hawaiian lobeliads, as well as tough and chewy ferns.  They had a very specific niche in the environmental order of early Hawaii, keeping vegetation chewed back, and encouraging other plants to thrive.

These birds have been found only on the oldest volcanic islands, suggesting they had many millennia to diverge in such a unique way, and fill a unique biological niche. Although it’s certainly not precise, mtDNA studies indicate time periods of over 3 million years with regards to genetic divergence from other Anatinae, making them pretty special indeed.

However, while our feathered friends were happily being herbivorous to the extreme in sunny Maui, other events were happening, with the expansion of a deadly species. Homo sapiens. The Polynesian peoples were constantly expanding their vistas. This ingenious culture which prized curiosity and adventure sailed the Pacific in deceptively fragile-looking canoes. It appears likely that these seafaring free spirits landed first on Samoan and Tongan shores during the equivalent of Europe’s Bronze Age, c 1500 BC but their eyes were always straining towards the horizon, and their minds moving to what may be found there.

The sand dune settlement at Pu‘u Ali‘I, on South Point, Big Island, has produced intriguing dates of limited human activity at around AD 124, give or take an error of about 60 years (calibrated, by the way). The artefacts found at Bellows sand dunes, Waimānalo on the island of Oahu appeared initially to reinforce an early date, with fish-hooks and adzes of a similar style to those found in the Marquesas Islands, which had been settled by Polynesian adventurers in late prehistory. Perhaps these were sheltering sailors, or castaways from a storm. At any rate, if these dates are even a wee bit right, and not the result of some pretty poor dating, this must have been the earliest colonisation phase, with a long lull between the initial arrival of pioneers and a more substantial colonisation, as the majority of archaeological sites date closer to between AD 800, and perhaps as late as AD 1000.

A fun map of the Hawaii islands. The older island of Oahu is in the top left of this image. Big Island can be seen in the bottom right.  (Public Domain image from here)

When these people arrived, they discovered an island of strange creatures. The flightless Moa Nalo had no natural enemies except a limited amount of carnivorous owls. The two legged creatures who leapt from their canoes were likely a source of curiosity to these beautiful birds who had existed in a state of balanced environmental peace for so long. They, like the Dodo on Mauritius Island, made for pathetically easy pickings for hungry humans. Extinction was imminent. We know that the Polynesians had hitch-hikers on board their canoes – sneaky little Rattus exulans, the Pacific rat. Its bones are within the same stratification as those of the Moa Nalo at Ewa plains sinkholes, on Oahu. Those have been pretty well dated to around AD 1160 (calibrated). It’s pretty likely R. exulans predated on the eggs of these giant ducks, which again, hastened their demise from the avifauna of the world.

It often infuriates me when history tries to tell us that our ancestors lived in a blissful state of harmony with their environments, when it just isn’t true. Ancient peoples were wasteful, destructive and thoughtless of their environment, which accounts for the recurring theme of extinctions and lack of managing natural resources. It’s an incredibly sad fact that such a little span of time separates us from these stunning and strange birds who were basically unknown until their bones started appearing in Hawaiian excavations during the boom years of the 1980s.  Moa Nalo, the lost fowl, were not lost to history any more.

There’s an interesting addendum to this story, which isn’t as quackers as it seems. The rewilding programme of Makauwahi Cave Reserve, on Kauai Island acknowledges that the modern environment is out of kilter with the original floral and faunal assemblages of even a millennia ago. We are not at a stage where we can do a ‘Jurassic Park’ on the creatures humans have slaughtered, but we can try to ensure the environment can recover from often destructive, invasive species. Makauwahi Reserve have introduced giant tortoises to chomp on the invasive species, allowing the native vegetation to flourish as it did when the Giant Hawaiian Ducks thrived on those remote Pacific shores.

Written by Rena Maguire (@JustRena)

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