The dinosaurs that became birds used their wings to climb * A dinosaur with four wings was discovered

The wings were used for climbing, only later for flight * The discovery that chicks use their wings to run on sloping terrain may change the theory describing how birds began to fly

The behavior of partridge chicks, which can quickly climb hay bales or climb a tree trunk, may shed light on the evolution of bird flight. In an article published last week in the journal "Science," Dr. Kenneth Dial from the University of Montana claims that feathered dinosaurs may have moved in a similar manner.

Dr. Dial happened to encounter the surprising behavior of the birds. He studied the flight development of the partridge chicks with the help of his teenage son. While he was away from home on a trip, his son recorded the flight development of the chicks and the growth of their feathers. To force the chicks to fly they were placed Hay cubes in front of them. When Dr. Dial returned from the trip, his son reported to him that the chicks were not behaving as expected. "They cheat," said the son, "instead of flying, they climb."

Dial decided to photograph the movement of the chicks with the help of photographic equipment that allows taking 1,000 pictures per second. The photographs revealed something that could not be discerned by ordinary observation. It turns out that the birds used their wings while moving on a steep slope. Dr. Dial called the phenomenon "running on an incline with the help of wings" and continued his research to gauge the effectiveness of the special running.

He found that newly hatched chicks were able to climb a slope of more than 45 degrees when they moved their wings strongly, and that four-day-old chicks were able to climb in this manner at a slope of more than 60 degrees. When they were 20 days old, some of the chicks were able to climb a vertical slope of 90 degrees for five meters, and there were even birds that managed to climb a slope of 105 degrees. "Nobody knew that birds could run up trees like that," said Dr. Kevin Padian of the University of California, Berkeley. The chicks performed significantly better than chicks whose feathers had been trimmed to some degree.

Dial assumes that the wings function like spoilers on a car. The flapping of the wings helps to pin the birds to the ground and prevents them from sliding. He measured the direction of action of the force created by the wings and found that it pushed the birds in the direction of the slope.

Until now, Dr. Dial has avoided taking part in the debate about the evolution of flight in birds. But now he feels he must. On one side of the debate are researchers who believe that the ability of birds to fly evolved when the first early birds climbed trees, jumped down and discovered that they can use the movement of certain organs to hover; hence the development of wings. But Dial claims that none of the hovering animals that exist now - for example squirrels, frogs and lizards - do not bother to move their limbs. Opponents of this theory claim that dinosaurs with "partial wings" learned to use them to rise above the ground.

According to Dr. Dial, "Both traditional explanations are correct, but neither one of them provides a complete picture." The explanation he offers is based on the assumption, which is supported by his research, that wings are not only used for flight (or hovering). The primitive wings were given to the primitive birds The ability to climb to high places thus provided them with an evolutionary advantage over other animals. When they were already in a high place - on a bush or a tree - the birds were found The ancients were in a position that allowed them to discover what the wings could do in the air.
Economist and New York Times

The discovery of a fossilized dinosaur with 4 wings will help explain the evolution of bird flight
The feathers on the arms and legs of the "Native Microraptor" allowed it to dart among the trees
25.1.2003
By: Tamara Traubman

Right: The fossilized skeleton discovered in China. Source: Li Rongshan. On the left is an illustration of a gentile microraptor. Its length reached about 77 centimeters Source: Portia Salon

Most evolution experts now hold the opinion that the ancestors of birds were dinosaurs. However, the question of how the ability to fly developed still remains unanswered. A fossil about 130 million years old, recently discovered in an ancient lake in the Liaoning region of northeastern China, may provide new information on the issue.

This is a fossil of an unknown four-winged dinosaur. The researchers - Dr. Xing Xu from the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing - gave it the name "Microraptor Gui", after a Chinese paleontologist who did a lot of digging in the area where the dinosaur was discovered.

Shaw and his team discovered six fossil remains of the winged dinosaur about two years ago. Their findings were published for the first time yesterday in the scientific journal "Nature". According to them, the microraptor Goi belonged to the dinosaur family Microraptor, which is included in a group of dinosaurs called dromaeosaurs. Scientists today believe that the dromaeosaurs are the closest group of dinosaurs to modern birds.
"The Microraptor Goi was a small animal," said Dr. Shaw. "Its entire length reached only about 77 centimeters." The dinosaur's arms and legs were covered in feathers, which the researchers described as "completely developed and modern." Also, its tail was decorated with a tuft Long feathers According to Shaw, the feathers of the Goi microraptor "are organized in a similar way to that of modern birds."

"It appears that it used its wings and its feathery tail to move from tree to tree, quite similar to the way modern flying squirrels move," said Richard Fromm, a professor of paleontology at the University of Kansas, who examined the fossils and wrote a commentary accompanying the study's publication. Indeed, the research report details several characteristics that support the assumption that the Goy microraptor could have died.
"The way the feathers are organized on its hind limbs could have provided it with an excellent 'air surface', which apparently allowed it to fly," Shaw said.
Over the years, the explanations for the development of the ability to fly have focused on two main theories: the "running theory", which holds that the ability to fly developed in animals that lived on the ground and developed strong legs, which allowed them to run and pick up momentum in order to rise; and the "tree theory", which holds that the ability to fly appeared in creatures that lived in trees and learned to move between trees. Soaring, claim holders of this theory, is simpler than the need to build up acceleration to take off from the ground.

According to Fromm, "the idea of ​​breastfeeding was first raised in 1915 by William Bibb, in a colorful article that seemed to see the newborn." Bibb proposed that the ability to fly evolved through an intermediate stage of four-winged creatures that roamed among the trees of the primeval forests.

"The Microraptor Goy looks like it could have come straight off the pages of Bibb's notebook," Fromm said. According to him, until now the idea of ​​motherhood was completely hypothetical, but the new fossils revive it. "I think that there is no other way to interpret this, except as new and amazing supporting evidence for the 'tree phase' in the evolution of the ability to fly," he said.

"Although early bird fossils have been discovered from the microraptor goi, stolid dinosaurs that resemble it may represent an evolutionary step between flightless dinosaurs and birds - which lost their hind wings at a later stage," Shaw said.

However, there are scientists who are not sure, because the Goy microraptor does have something to do with the development of the ability to fly. According to Larry Whitmer of Ohio University, even if the microraptor did fly, it may have been a "failed experiment" among one branch of dromaeosaurs, and that current bird flight evolved independently from another ancestor.

The archeopteryx spread its wings

The ancient birds probably started flying millions of years earlier than thought

13.8.2004
By: John Noble Wilford New York Times, Haaretz, Walla!
Archeopteryx fossil. The size of the brain - like that of an eagle or a sparrow. Photo: Natural History Museum in London

Archeopteryx, the earliest bird known to science, did indeed have the brain of a bird, and that is not to be taken lightly. According to a new study, the brain size of the animal - which is considered a clear example of the transformation of certain reptiles, probably dinosaurs, into today's birds - is unequivocal evidence that it had the necessary data for flight. Another conclusion of the study, which was published last week in the journal "Nature", is that the birds probably began to fly millions of years earlier than scientists had previously thought.

The researchers, from the Natural History Museum in London, based their findings on a first-of-its-kind study, in which an X-ray examination was performed followed by a reconstruction of the braincase and inner ear of a 147-million-year-old Archeopteryx fossil found in Germany. The skeleton, embedded in a bed of limestone, is of a creature the size of a crow.

The researchers found that in terms of size, shape and volume, the brain of Archaeopteryx was similar to that of the modern eagle or sparrow. Measurements of the semicircular canals - the balance mechanism inside the ear - revealed that Archaeopteryx had "the neurological and structural characteristics necessary for flight".

Previous studies of Archeopteryx's feathered wing and tail and its avian anatomy—including a prominent clavicle—supported the hypothesis that it was capable of flight, at least to some degree. But the research team, led by Angela Milner, a paleontologist at the British Museum, wrote that prior to the current study, "there was little knowledge of the extent to which Archeopteryx's mind and special senses were adapted to flight." In a statement published by the museum, Milner wrote, "If flight was already at such an advanced stage during the time of Archeopteryx, this means that there were birds that flew millions of years earlier than we thought."