how do birds fly wikipedia

Around 350 BCE, Aristotle and other philosophers of the time attempted to explain the aerodynamics of avian flight. Even after the discovery of the ancestral bird Archaeopteryx which lived over 150 million years ago, debates still persist regarding the evolution of flight. There are three leading hypotheses pertaining to avian flight: Pouncing Proavis model, Cursorial model, and Arboreal model. The Berlin

In March 2018, scientists reported that Archaeopteryx was likely capable of flight, but in a manner substantially different from that of modern birds.[1][2]

Lift change

The principles of bird flying are comparable to those of aviation The airflow on the wing, which is an airfoil, produces lift force. Because of the air’s higher pressure below and lower pressure just above the wing, lift force is produced.

Flight characteristics edit

Four physical forces—lift, weight, drag, and thrust—must be favorably combined for flight to occur. For birds to maintain a balance between these forces, they need specific physical traits. All flying birds, with the exception of hummingbirds, have asymmetrical wing feathers that aid in producing thrust and lift. Because of friction, anything moving through the air creates drag. A bird’s aerodynamic body can reduce drag, but its tail and feet will increase drag when it stops or slows down. The biggest challenge birds face when trying to fly is weight. If an animal’s absolute weight is decreased, it can achieve flight more readily. Due to rapid evolutionary changes and a period of size reduction during the Middle Jurassic, birds evolved from other theropod dinosaurs. [3] As flying birds evolved, their gonads shrank during the mating season, they lost teeth, and their bones fused together, all of which contributed to a further decrease in relative weight. A thin, keratin-based bill took the place of the teeth, and the bird’s gizzard processed its meal. Additional sophisticated anatomical features that evolved for flight include an enlarged cerebellum for fine motor coordination and a keel for the attachment of flight muscles. However, these were not strict requirements for flight; the earliest birds had teeth, a small keel at most, and relatively unfused bones. These were gradual changes. Although pneumatic bone, which is hollow or packed with air sacs, has frequently been viewed as a weight-loss adaptation, non-flying dinosaurs already possessed it, and birds’ skeletons are generally not lighter than those of mammals of the same size. The furcula, a bone that improves skeletal bracing for flight-related stresses, is comparable. [citation needed].

The majority of an avian’s wing motions occur at the shoulder, where a complex interplay of forces is involved in the mechanics of the wing. These operations rely on the precise balance of loads on the wing from inertial, gravitational, and aerodynamic sources as well as from the muscles, ligaments, and articular cartilages. [4].

Birds fly primarily using their pectoralis and supracoracoideus muscles, which are located in their wings. The largest muscle in the wing, the pectoralis, serves as the main pronator and depressor of the wing. The principal elevator and supinator is the second-largest, supracoracoideus. Distal wing muscles are another set of muscles that help the bird fly. [5].

Feathers were present on the bodies of many dinosaur species before they appeared on birds. Over tens of millions of years, as the animals’ wings developed, natural selection made feathers more common among them. When in flight, a bird’s smooth feathered body helps to minimize friction. The feathers in the tail also aid in the bird’s ability to glide and maneuver. [7].

Wing-assisted incline running editMain article:

Inspired by the observation of young chukar chicks, the WAIR hypothesis proposes that wings developed their aerodynamic functions as a result of the need to run quickly up extremely steep slopes like tree trunks, for example to escape from predators. This theory is a version of the “cursorial model” of the evolution of avian flight, according to which birds wings originated from forelimb modifications that provided downforce, enabling the proto-birds to run up extremely steep slopes like the trunks of trees. Keep in mind that in this situation, birds require downforce to increase the grip on their feet. [13][14] It has been suggested that early birds, such as Archaeopteryx, lacked the shoulder mechanism that allows modern birds’ wings to produce quick, forceful upstrokes; since upstrokes are what produce the downforce that WAIR depends on, it appears that early birds were unable to produce WAIR. Nevertheless, a study that discovered that the primary factor preventing a body from successfully accelerating toward a substrate during WAIR was the lift produced by the wings suggested that neuromuscular control or power output, rather than the external wing morphology itself, constrained the onset of flight ability and that partially developed wings that were not yet capable of flight could in fact provide useful lift during WAIR. [16] Moreover, analysis of the work and power requirements for the contractile behavior of the extant bird pectoralis during WAIR at various angles of substrate inclination showed that these requirements gradually increased as WAIR angles increased and during the transition from WAIR to flapping flight. This offers a model for the gradual adaptation of transitional forms to meet the work and power requirements to climb increasingly steeper inclines using WAIR and the gradual increases from WAIR to flight, representing the evolutionary transition from terrestrial to aerial locomotion. [17].

From the moment they hatch, birds use wing-assisted inclined running to enhance their ability to move. This also applies to birds and other feathered theropods whose wing muscles are incapable of producing enough force for them to fly, demonstrating how this behavior may have developed to support these theropods before eventually leading to flight. [18] Birds grow from hatchlings to fully grown birds, demonstrating the transition from wing-assisted incline running to flight. When they grow and can exert enough force, they gradually modify their wing strokes for flight, starting with wing-assisted incline running. These phases of transition, which precede flight, are behavioral as well as physical. The changes that occur during a hatchling’s life can be linked to the larger-scale evolution of flight. Protobirds and hatchlings may have had comparable physical characteristics, such as wing size and behavior. The size and muscle force of a wing determine how far it can flap. The protobirds’ wings were not able to support flight even when they were using the proper arboreal or cursorial model, but they most likely acquired the behaviors required for the model when they hatched, just like modern birds do. There are similar steps between the two. [19] In babies, wing-assisted incline running can also provide a beneficial lift, although it is much less than in juvenile and adult birds. It was discovered that this lift causes the body to accelerate when climbing an incline and eventually results in flight as the bird grows. [20].