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Argentavis magnificens – the largest flying bird in the history

Argentavis – (Argentavis magnificens)

The largest flying bird in the history of the world

Millions of years ago everything was in XXL size, even the modern giant flying birds – Andean condors (Vultur gryphus) would look more like little pigeons when compared to the largest bird ever.

Classification

  • Kingdom: Animalia
  • Phylum: Chordata
  • Class: Aves
  • Order: Cathartiformes (disputed)
  • Family: †Teratornithidae
  • Genus:Argentavis
  • Species:Argentavis magnificens
Argentavis
Argentavis (Argentavis magnificens).

Range and dating

The remains of the Earth’s largest bird were discovered in central and north-east Argentina. It has been estimated that it lived about 6 million years ago in the Miocene epoch.

Characteristics

Argentavis was an undeniably large bird, its torso was about 1.26 m (4.13 ft) long, its height was located probably in the range of 1.7 – 2 m (5.6 – 6.5 ft), with wingspan reaching 7 meters (23 ft), weighing up to 70 – 78 kg (154 – 172 lb).

To compare, presently the widest wingspan among birds is 3.7 meters (12.1 ft), the wandering albatross (Diomedea exulans) being the title holder. Another giant bird close to the record in this category is the Andean condor, which is the closest relative for Argentavis, reaching a wingspan of 3.2 meters (10.5 ft) and weighing about 15 kg (33 lb). The sarus crane (Grus antigone) is presently the tallest bird in the world, being as tall as Argentavis in its time. Even the heaviest bustards or swans are not even close in terms of weight to the gigantic bird from Argentina.

Only the pterosaurs could be leveled opponents for the Argentavis, yet our dear readership already knows that as they are familiar with the king of the skies – Quetzalcoatlus.

Argentavis
Argentavis (Argentavis magnificens).

Manner of flying

Researchers are not entirely sure how such a massive animal could take off the ground. Throughout the years a few theories were proposed: the small sternum suggests that the muscles that are most vital for flying were reduced when compared to other flying birds. This means that despite their vast area and the bird’s wingspan, they were not strong enough to be flapped as many birds’ wings are.

Air currents

As a result, it is possible that this animal’s flight was based on currents, like a glider, whilst the wing flapping was needed only during takeoff and landing.

 As an animal adapted to gliding flights, it surely took advantage of wind and current changes, being able to manipulate the flight altitude and speed through updrafts (rising air currents). Through this technique the bird could save substantial amounts of energy.

It is also possible that the air currents vital for takeoffs and the giant size of its wings caused the bird to hit the ground with its flapping flight feathers during the very first seconds of flight. In such case the theory engaging rapid wing flapping during takeoff seems somehow questionable.

Argentavis
Argentavis (Argentavis magnificens) – taking advantage of updrafts in the flying process.

However it is more likely for Argentavis to spread its wings in an upright position, waiting for adequate updrafts. In such position it would not grow tired, as whole wings were surrounded by air flow and the moment our bird caught a right current, it leaped up thanks to its strong legs.

The starting process is one of the most dangerous (if not THE most dangerous) aspects of flying – much depends on the body position just before takeoff. If all went well, Argentavis flew horizontally-orientated, flapping its wings only occasionally to benefit most from the air currents.

Argentavis
Argentavis (Argentavis magnificens) – found remains’ spots – see interesting facts below.

Behavior

Its dietary preferences remain a mystery even today, yet the bird was a carnivore, presumably. However it was not an active hunter, as e.g. eagles, for their body shape and relatively weak breast muscles would not allow it. Conceivably it feasted on carrion, just like condors.

Scavenging would also require the bird to be proactive, which would force it to store reserves of calories to survive. Large size has become the root of many problems, as numerous potential opponents awaited it on the ground – e.g. predatory marsupials from the Thylacosmilus genus.

Nevertheless it is worth remembering that the largest Miocene predators from South America were other birds – flightless seriema birds from the Phorusrhacidae family (commonly known as terror birds). These birds had lost their ability to fly, yet the largest members of the family – Phorusrhacos or Kelenken could hunt for a truly massive prey, which resulted in considerable amounts of carrion – a perfect opportunity for Argentavis.

Argentavis
Argentavis (Argentavis magnificens) – reconstruction.

Breeding and longevity

Although nobody can confirm with all certainty what was the life of this gigantic bird like, its size and probably a stationary lifestyle (in comparison to lives of active predators) suggest that it had a very long life expectancy.

Due to its size it had no natural enemies in the air, even the large or medium-sized land predators could threaten it individually. Therefore its fiercest opponent could be the above mentioned large seriemas, yet Argentavis could flee from danger thanks to its ability to fly – flightless birds were also helpless. All these factors have led paleontologists to a conclusion that this bird lived a long and not very stressful life.

Argentavis
Argentavis (Argentavis magnificens) – reconstruction in the Natural History Museum in Los Angeles. The person standing by the bird is Kenneth Campbell PhD, the author of genus and species description, alongside with E.P. Tonni.

K-selection strategy

If the above information was true, it is possible for Argentavis to follow the so called K-selection strategy – it is an example of animal living in its own ecosystem with very little population fluctuations (relatively low reproductive rate). It prevents the species from the exhaustion of food supply, which is possible even for scavengers.

Following the K-selection strategy these birds conceivably took care of the offspring for a very long, yet there were few young birds in a single hatch. This allowed the chick to have more time for a healthy development, which was also intertwined with low mortality rate among young birds. Argentavis probably laid 1 or 2 eggs at best, every weighing more than 1 kg (2.2 lb) , with hatching taking place once every two years (as for modern birds of prey).

Argentavis
Argentavis (Argentavis magnificens) – size comparison.

Detailed characteristics / size

Argentavis (Argentavis magnificens)

Size

  • Torso length: 1.26 m (4.1 ft)
  • Height: 1.7 – 2 m (5.6 – 6.6 ft)
  • Wingspan: about 7 m (23 ft)
  • Weight: 70 – 98 kg (154 – 216 lb)
  • Wing area: 8.11 m2 ( 87 ft2)

Range

  • Areas of occurrence: South America, present-day Argentina
  • Dating: about 6 million years ago
  • Epoch: Late Miocene
  • Age: Messinian

 

Argentavis
Argentavis (Argentavis magnificens) – size comparison. Argentavis on the left, Haast’s eagle to the right, human in the background.

Argentavis (Argentavis magnificens) – interesting facts

  • Name of the species may be translated to ‘mighty/magnificent Argentinean bird’.
  • Its wingspan was nearly as wide as the Cessna 152 plane.
  • A similar wingspan had recently discovered Pelagornis sandersi 6.1 – 7.4 m (20 – 24 ft).
  • Species closely related to Argentavis, equally impressive, inhabited the West Coast of North America not so long ago – they surely interacted with Homo sapiens.
  • We cannot rule out the possibility of Argentavis living in a much wider habitat than we presume.
  • This bird was known for its massive, strong legs and large feet, which made moving on the ground relatively easy. The beak was hook-shaped and substantially large.
  • The discovery was made by E. Tonni and R. Pascual working for the La Plata National Museum in Argentina. The remains were found near the Salinas Grandes de Hidalgo in La Pampa province, about 640 km (398 mi) south-west from Buenos Aires. The find consisted of skull fragments, incomplete left humerus, radial bone, metacarpal bones and tarsus bones.
  • The main image obviously does not present the Argentavis as we were not able to take a photo of it during our expeditions (but we’re close 😉 )
Argentavis
Argentavis on the bottom (blue) with the bald eagle at the top (green).

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