Bird flight evolution, new research

This video from Canada says about itself:

The chukar partridge (Alectoris chukar)

Chukar partridge were introduced to the Kamloops area in the early 1950’s. They established themselves quickly and expanded in numbers due in a large part to the poor quality of our range land. With improved grazing practices and aggressive weed control the habitat has shrunk for these beautiful birds.

From Wildlife Extra:

Falling chicks could reveal the mysterious origins of flight

Two researchers from the University of California, Berkeley, may have just disproved a widely-accepted theory of how the origins of flight began.

Dennis Eva Evangelista, post-doctoral researcher at University of North Carolina, Chapel Hill, and Robert Dudley, UC Berkeley professor of integrative biology, undertook research to assess how baby birds (in this case the team used chukar partridges) react when they fall upside down.

Their results revealed that even birds that were just one-day old successfully flapped their wings in order to right themselves when they fell.

In the nest, the chicks used their wings to flip or roll themselves around. Nine days after hatching, 100 per cent of birds that were analysed in the study were found to have developed coordinated flapping and body pitch control, enabling them to right themselves.

“These abilities develop very quickly after hatching,” said Evangelista, who emphasised that no chicks were harmed during the research. “The results highlight the importance of manoeuvring and control in development and evolution of flight in birds.”

Dudley had argued for more than a decade against the popular theory of wing-assisted incline running (WAIR), which theorises that flight originated in theropod dinosaurs – the ancestors of birds – when they used symmetric wing flapping while running up an incline.

This theory argues that wings assisted running by providing lift, and that the ability to steer or manoeuvre is absent early on in the evolution of flight. To test this, the researchers tested the chicks to see if they flapped their wings while running up an incline. However, none of the birds did.

Dudley’s theory is that flight developed in tree-dwelling animals falling, and then evolving the ability to glide and fly. He believes that midair manoeuvrability preceded the development of flapping flight, allowing the ancestors of today’s birds to use their forelimbs as rudimentary wings.

The results of the study reveal that aerial righting using uncoordinated, asymmetric wing flapping, is very early development. “This experiment illustrates that there is a much broader range of aerodynamic capacity available for animals with these tiny, tiny wings than has been previously realised,” Dudley explains.