This led paleontologist Xu Xing in 2003 to describe the first specimen to preserve this feature as a "four-winged dinosaur" and to speculate that it may have glided using all four limbs for lift.

After the forgery was revealed by Xu Xing of Beijing's Institute of Vertebrate Paleontology and Paleoanthropology, Storrs L. Olson, curator of birds in the National Museum of Natural History of the Smithsonian Institution, published a description of the Microraptor's tail in an obscure journal, giving it the name Archaeoraptor liaoningensis in an attempt to remove the name from the paleornithological record by assigning it to the part least likely to be a bird.

[6] Since the two names designate the same individual as the type specimen, Microraptor zhaoianus would have been a junior objective synonym of Archaeoraptor liaoningensis and the latter, if valid, would have had priority under the International Code of Zoological Nomenclature.

[9] The first specimen referred to Microraptor represented a small individual and included faint feather remnants, but was otherwise not well preserved and lacked a skull.

[11] Czerkas et al. (2002) diagnosed the genus on the basis of having primary feathers (which in the authors' opinion made it a bird), a co-ossified sternum, a tail consisting of 28 to 30 vertebrae and a third finger with a short phalanx III-3.

[15] A new specimen of Microraptor, BMNHC PH881, showed several features previously unknown in the animal, including the probably glossy-black iridescent plumage coloration.

[18] In 2010, it was reported that there were over 300 undescribed specimens attributable to Microraptor or its close relatives among the collections of several Chinese museums, though many had been altered or composited by private fossil collectors.

[11] In his discussion of Cryptovolans in this book, Czerkas strongly denounces Norell's conclusions; "The misinterpretation of the primary wing feathers as being from the hind legs stems directly to [sic] seeing what one believes and wants to see".

[19] Czerkas's interpretation of the hindleg feathers noted by Norell proved to be incorrect the following year when additional specimens of Microraptor were published by Xu and colleagues, showing a distinctive "hindwing" completely separate from the forelimb wing.

[21] The work of Turner et al. (2007) suggested that the ancestral dromaeosaur could not glide or fly, but that there was good evidence that it was small-bodied (around 65 cm long and 600–700 g in mass).

Though not apparent in most fossils under natural light, due to obstruction from decayed soft tissue, the feather bases extended close to or in contact with the bones, as in modern birds, providing strong anchor points.

[30] Some paleontologists have suggested that feathered dinosaurs used their wings to parachute from trees, possibly to attack or ambush prey on the ground, as a precursor to gliding or true flight.

[31] In their 2007 study, Chatterjee and Templin tested this hypothesis as well, and found that the combined wing surface of Microraptor was too narrow to successfully parachute to the ground without injury from any significant height.

[23][31] Wind tunnel experiments have demonstrated that sustaining a high-lift coefficient at the expense of high drag was likely the most efficient strategy for Microraptor when gliding between low elevations.

[33][26] Describing specimens originally referenced as a distinctive species (Cryptovolans pauli), paleontologist Stephen Czerkas argued Microraptor may have been a powered flier, and indeed possibly a better flyer than Archaeopteryx.

Today, most scientists agree that Microraptor had the anatomical features expected of a flying animal, though it would have been a less advanced form of flight compared to birds.

In the ancestral anatomy of theropod dinosaurs, the shoulder socket faced downward and slightly backward, making it impossible for the animals to raise their arms vertically, a prerequisite for the flapping flight stroke in birds.

Studies of maniraptoran anatomy have suggested that the shoulder socket did not shift into the bird-like position of a high, upward orientation close to the vertebral column until relatively advanced avialans like the enantiornithes appeared.

[26] Stephen Czerkas, Gregory S. Paul, and others have argued that the fact Microraptor could fly and yet is also very clearly a dromaeosaurid suggests that the Dromaeosauridae, including later and larger species such as Deinonychus, were secondarily flightless.

[38] Sankar Chatterjee suggested in 2005 that, in order for Microraptor to glide or fly, the forewings and hindwings must have been on different levels (as on a biplane) and not overlaid (as on a dragonfly), and that the latter posture would have been anatomically impossible.

The feathers not directly employed in the biplane wing structure, like those on the tibia and the tail, could have been used to control drag and alter the flight path, trajectory, etc.

The resulting data showed that Microraptor did have the requirements to sustain level powered flight, so it is theoretically possible that the animal flew, as opposed to gliding.

Alexander's team used a specimen of Microraptor which was crushed flat to make their model, which Brougham and Brusatte argued did not reflect its actual anatomy.

[40] However, Hartman and colleagues suggested that Hesperonychus is not a dromaeosaur, but actually an avialan close to modern birds like Balaur bondoc based on phylogenetic analyses in 2019.

A 2010 study by Corwin Sullivan and colleagues showed that, even with the wing folded as far as possible, the feathers would still have dragged along the ground if the arms were held in a neutral position, or extended forward as in a predatory strike.

[23] In 2010 researchers announced that further preparation of the type fossil of M. zhaoianus revealed preserved probable gut contents, and a full study on them was later published in 2022 by David Hone and colleagues.

These consisted of the remains of a mammal, primarily a complete and articulated right foot (including all tarsals, metatarsals, and most of the phalanges) as well as the shafts of additional long bones and potentially other fragments.

[44][45] In the December 6, 2011 issue of Proceedings of the National Academy of Sciences, Jingmai O'Connor and coauthors described a specimen of Microraptor gui containing bones of an arboreal enantiornithean bird in its abdomen, specifically a partial wing and feet.

They further argued that the specimen showed a probable adaptation to a fish-eating diet, pointing to the first three teeth of the mandible being inclined anterodorsally, a characteristic often associated with piscivory.

The Indrasaurus bones lacked marked pitting and scarring, indicating that the Microraptor died shortly after eating the lizard and before significant digestion had occurred.