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Thursday, May 10, 2012

Birds of Prehistory, Part II

On occasion, I write articles for the birding group I belong to (Illinois Young Birders http://illinoisyoungbirders.org/), mostly about prehistoric birds or something like that. The next issue coming up features my article Birds of Prehistory Part 2 (Part 1 is in an earlier issue and is way less good than this one). Here's the text of the article for those who are interested:
Quick, say ‘bird’. What’s the first thing that pops up in your mind? A sparrow? Gull? Ostrich? These forms may seem familiar today; we’ve all seen birds in the wild and in zoos, but before man there were much, much stranger birds that lived.
The Enantiornithes: Conquerors of the Mesozoic
            One of the most successful groups of birds that ever existed was the enantiornithes, which colonized the world of the dinosaurs for sixty six million years. If you’ve ever watched Walking with Dinosaurs, then you’ve most likely seen enantiornithes; the birds attacking the pterosaur (similar to hummingbirds and other birds which will attack hawks if they stray too close to their nests) were enantiornithes known as Iberomesornis. A small (finch-sized) bird, Iberomesornis inhabited what is now Spain nearly 125mya, living near rivers and deltas with oddities such as the dinosaur Pelecanimimus, which can be imagined as a flightless pelican, and the hump-backed Concavenator, a carnivore related to Allosaurus. Known as the “opposite birds”, due to the arrangement of the scapula/coracoid bones filled the niches that are inhabited by passerines, sapsuckers and raptors today. We’ve already talked about one in the first part of BOP, known as Avisaurus, which was like a red-tailed hawk with a meter-wide wingspan and teeth. A Chinese form, Longipteryx, would have filled the niche the kingfishers occupy today. However, all good things must come to an end, and even though the enantiornithes stormed through five of the world’s continents, they went extinct along with non-avian dinosaurs 65mya.
Killer Ducks and Seriemas: Birds Hold Their Grip
            The Cenozoic, the age we live in now, is often called the Age of the Mammals, due to the fact mammals were evolving more rapidly and taking over niches the non-avian dinosaurs left. Rhino-like uintatheres and brontotheres filled the niche that non-avian dinosaurs like Triceratops left behind; the cougar-like Patriofelis was the apex mammalian predator. But dinosaurs, in the form of birds, weren’t giving up just yet. For 16 million years, a 5-7ft tall bird terrorized North America and Europe. Known as Gastornis, this bird wasn’t large enough to take on the uintatheres that inhabited the land at the time, but they were large enough to kill just about anything else in their environments; pygmy horses in North America, anteater cousins in Europe, etc. They faced little competition from mammals, except for the aforementioned Patriofelis and the jackal-sized Arctocyon. And while Gastornis, an anseriforme, died out 40 million years ago and mammals took over, South America wasn’t ready for mammals’ rule yet.
            They came in the form of terror birds. When we went to the Field Museum, a model of one, Andalgalornis, was in the room where we saw the hawk. Terror birds reigned over South America for sixty million years, their rule ending just 2 million years ago. Related to seriemas (cariamas), they were apex predators, most of them nimble and agile, striking down prey with their sharp talons and beaks. Phorusrhacos, a Gastornis-sized terror bird, was anachronistically featured alongside sabertooth cats in Walking with Beasts. The largest terror birds were Titanis and Kelenken, 8ft and 10ft tall, respectively. The former actually reached North America and managed to cause terror (no pun intended) for another three million years, running alongside prey at speeds of 65 kph, rivaling that of the ostrich. And then, for unknown reasons (probably niche competition), they all died out, and were replaced by carnivores such as wolves and sabertooth cats.
Pseudodontorns: Pterosaurs Rise Again
            Seventy-five million years ago, a large pterosaur known as Pteranodon, soared over Kansas, when it was an interior sea, and dwelled on cliffs, consuming fish. Fifty-five million years later, a similar scene is repeated and the actors are birds. Known as the pseudodontorns, these birds are known in the fossil record from 58-2mya, with the most famous being Osteodontornis, which lived 20mya in North America. This bird had the second-largest wingspan in avian history, surpassed only by a giant South American vulture (bonus points if you know its name). The pseudodontorns were odd birds, with the largest possessing wingspans of twenty feet. They also had bills lined with false teeth (hence, their group name means ‘false tooth birds’), similar to the projections on mergansers’ bills. These giant birds would have filled the niche that some pterosaurs held in the Mesozoic era, and the niche albatrosses fill now. When they went extinct 2.5mya, Olduvai stone tools were just being invented.
Samrukia and Gargantuavis: Giant Birds of the Mesozoic
            Everyone knows the Mesozoic as the heyday of the non-avian dinosaurs. They reached immense sizes, so big that no other animal could get bigger than a rat when they were alive. But that view is inaccurate. In reality, mammals, birds, and reptiles flourished into various niches and sizes. Badger-sized mammals fed on baby dinosaurs, crocs the size of SUVs walked around on land and terrorized life. And even the birds were getting huge. On the islands of Late Cretaceous France, a bird as tall as man roamed. Possibly related to the patagopterids mentioned in Part 1, it was an herbivore, somewhat like a moa, and its name was Gargantuavis. But this wasn’t the only giant bird around, or so it is thought. Very recently discovered, the Kazakh Samrukia was a bird that must have stood 10ft tall. However, its classification is disputed at the moment. Since it is only known from a jawbone, some say it could be a pterosaur and some say it could be an oviraptorosaur dinosaur. Whatever the case is, it was gigantic, and proves that dinosaurs weren’t the only big ones around.
Presbyornis: The Flamingo-duck
We end this article on a peculiar bird that appeared just three million years after the non-avian dinosaurs were wiped out (and it could have possibly lived alongside the last dinosaurs, if scant fossil remains prove to be from it). Named Presbyornis, it was an early anseriform, which most professional birders would recognize as the order that includes ducks, geese, swans, screamers, and magpie geese. While an individual could weigh in at goose-swan size (14-33lbs), Presbyornis was much more gracile, with longer legs, standing around 3-5ft tall. In fact, it resembled a flamingo with the head of a dabbling duck, feeding on small animals and water plants. Presbyornis proved to be a successful design, living for seven million years before dying out. The author hopes you learned some new bird material from this article.


  1. If Samrukia was a bird or oviraptorosaur, then it does nothing to dispel the idea that "dinosaurs were the only big ones around". (But the pterosaur interpretation appears to be more likely at the moment to begin with.)

    1. That's true, guess I was thinking "non-avian dinosaur" (though if it was an oviraptorosaur it would be one of those) and didn't translate it to paper.