Anchiornis is notable for its proportionally long forelimbs, which measured 80% of the total length of the hindlimbs.
This is similar to the condition in early avians such as Archaeopteryx, and the authors pointed out that long forelimbs are necessary for flight.
Anchiornis also had a more avian wrist than other non-avialan theropods.
The authors initially speculated that it would have been possible for Anchiornis to fly or glide.
However, further finds showed that the wings of Anchiornis, while well-developed, were short when compared to later species like Microraptor, with relatively short primary feathers that had rounded, symmetrical tips, unlike the pointed, aerodynamically proportioned feathers of Microraptor.
A 2016 study of potential flight performance in early paravians concluded that while juvenile Anchiornis specimens may have been able to use their wings to assist running up an incline, and could possibly have achieved flapping flight if a very high-angle flapping wing stroke was used, the larger adult specimens would not have gained any aerodynamic benefit from their wings—they were simply too heavy compared to their total wing area.
The same study found that flapping the wings while running would have resulted in a small (10%) increase to its running speed.
Similarly, use of the wings during leaping would have resulted in a 15 to 20% increase in height and distance.
Notably, Anchiornis seems to have lacked a breastbone (sternum), which may have been made of cartilage rather than bone, as in more primitive theropods.

Anchiornis has hindleg proportions more like those of more primitive theropod dinosaurs than avialans, with long legs indicating a fast-running lifestyle.
However, while long legs normally indicate a fast runner, the legs and even feet and toes of Anchiornis were covered in feathers, including long feathers on the legs, similar to those in the hindwings of Microraptor.
Long leg feathers on the lower legs may have slowed the running speed of Anchiornis.
In modern birds, especially those that live on the ground, the lower legs tend to show reduction or even loss of feathers.
The hind wings of Anchiornis were smaller and made of more curved, symmetrical feathers than those of Microraptor, suggesting that they were used mainly for display rather than flight.
However, they might still have granted the animal some kind of aerodynamic advantage, even if their primary purpose was for display or some other function.

The skeletal structure of Anchiornis is similar to Eosinopteryx, which appears to have been a capable runner due to its uncurved rear claws and absence of flight feathers on its tail or lower legs.
Anchiornis shared a similar body plan and the same ecosystem as Eosinopteryx, suggesting different niches and a complex picture for the origin of flight.

Like many modern birds, Anchiornis exhibited a complex pattern of coloration with different colors in speckled patterns across the body and wings, or "within- and among-feather plumage coloration."
In modern birds, such color patterning is used in communication and display, either to members of the same species (e.g. for mating or territorial threat display) or to threaten and warn off competing or predatory species.
Anchiornis is notable for its proportionally long forelimbs, which measured 80% of the total length of the hindlimbs. This is similar to the condition in early avians such as Archaeopteryx, and the authors pointed out that long forelimbs are necessary for flight. Anchiornis also had a more avian wrist than other non-avialan theropods. The authors initially speculated that it would have been possible for Anchiornis to fly or glide. However, further finds showed that the wings of Anchiornis, while well-developed, were short when compared to later species like Microraptor, with relatively short primary feathers that had rounded, symmetrical tips, unlike the pointed, aerodynamically proportioned feathers of Microraptor. A 2016 study of potential flight performance in early paravians concluded that while juvenile Anchiornis specimens may have been able to use their wings to assist running up an incline, and could possibly have achieved flapping flight if a very high-angle flapping wing stroke was used, the larger adult specimens would not have gained any aerodynamic benefit from their wings—they were simply too heavy compared to their total wing area. The same study found that flapping the wings while running would have resulted in a small (10%) increase to its running speed. Similarly, use of the wings during leaping would have resulted in a 15 to 20% increase in height and distance. Notably, Anchiornis seems to have lacked a breastbone (sternum), which may have been made of cartilage rather than bone, as in more primitive theropods.
Anchiornis has hindleg proportions more like those of more primitive theropod dinosaurs than avialans, with long legs indicating a fast-running lifestyle. However, while long legs normally indicate a fast runner, the legs and even feet and toes of Anchiornis were covered in feathers, including long feathers on the legs, similar to those in the hindwings of Microraptor. Long leg feathers on the lower legs may have slowed the running speed of Anchiornis. In modern birds, especially those that live on the ground, the lower legs tend to show reduction or even loss of feathers. The hind wings of Anchiornis were smaller and made of more curved, symmetrical feathers than those of Microraptor, suggesting that they were used mainly for display rather than flight. However, they might still have granted the animal some kind of aerodynamic advantage, even if their primary purpose was for display or some other function.
The skeletal structure of Anchiornis is similar to Eosinopteryx, which appears to have been a capable runner due to its uncurved rear claws and absence of flight feathers on its tail or lower legs. Anchiornis shared a similar body plan and the same ecosystem as Eosinopteryx, suggesting different niches and a complex picture for the origin of flight.
Like many modern birds, Anchiornis exhibited a complex pattern of coloration with different colors in speckled patterns across the body and wings, or "within- and among-feather plumage coloration." In modern birds, such color patterning is used in communication and display, either to members of the same species (e.g. for mating or territorial threat display) or to threaten and warn off competing or predatory species.
Anchiornis