Swifts – Living on the Wing

January 18, 2015 by  
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With their forked tails and scythe-shaped wings, swifts herald the arrival of spring in Europe and are seen as the bringers of rain in parts of Africa where they spend their winters. These amazing birds spend almost their entire lives in flight, so much so that their legs are small and too weak to support them for long when perching, explaining why their family name, Apodidae, is taken from the Greek word meaning ‘without feet’. Spine-tailed swifts, also known as white-throated needletails, have been measured as flying up to speeds of 105 mph (169km/h), while common swifts are known to routinely reach speeds of 70 mph (112 km/h).

Although they resemble swallows, swifts are placed in the same order as hummingbirds, Apodiformes, while swallows are of the order Passeriformes. Their similarities are attributed to convergent evolution, a phenomena where differing species develop similar traits due to lifestyle adaptations, in this case their habit of catching insects in flight.

Distances are immaterial to swifts, as they can easily fly 500 miles in a day. Most swifts remain airborne from when they fledge to the first time they breed – a period of roughly four years. It’s been estimated that in a swift’s lifetime it will cover a distance of around 1.28 million miles. They even roost on the wing, circling gently for hours as the two sides of their brains take turns in sleeping. Swifts only nest to raise their young, and are fond of doing so inside roofs of houses. Parents can gather and carry as many as 1,000 insects to feed their young, making them very effective insect controllers. When the fledglings leave the nest, they all take to the skies and so the cycle continues.

When swifts are feeding in the late afternoon, they swoop through the air in a series of aerobatics that are fascinating to watch. As is the case with hummingbirds, swifts are able to rotate their wings in a manner that keeps them fully extended and rigid, delivering power on both the upstroke and downstroke, thereby increasing their speed and maneuverability. No other bird species are able to do this. So if you happen to have the good fortune to see swifts in action, take some time to appreciate their unique characteristics.

Possible Insights into the Evolution of Flight

June 28, 2011 by  
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A study run by the University of Montana might just be able to bring clarity to the evolution of flight, as Brandon Jackson and his team conducted research into bird flight. Their findings have recently been published in the Journal of Experimental Biology. The art of flap-running by birds is the major factor discussed in the study, showing that this method could have been used by once flightless birds, and is still used by birds today to enable them to propel themselves forward. Jackson wanted to know why.

It seems that birds today will often flap their wings while walking up a slope or incline, to enable them to move forward. It is believed that this flap-run movement enables birds to take to flight. It is the same technique that is adopted by chicks, as they are unable to fly when they are born, and need to learn how to conquer this method of movement. The fact that birds are not born with flight abilities, has led researchers to believe that this very method was part of the evolution of flight. This interesting method of movement was noticed by Ken Dial while he was studying chuckars, which are part of the partridge family. After talking to locals and ranchers who have constant contact with these birds, they confirmed that most of the chuckars would rather flap-run up a hill or cliff, as it seems that it takes a lot less energy for them to flap-run instead of flying. This became very intriguing to researchers and they decided to measure how much power is being used while flap-running as opposed to flying.

They managed to record this by implanting electrodes into pigeons’ flight muscles, which could then record the muscle activity. Pigeons are very good flyers, but given inclines and ramps, the difference between flying up the incline and flap-running was analyzed. It was found that much less power was used during flap-running and that this method would therefore be crucial for chicks to learn how to fly, as well as for birds that are still developing their plumage to escape predators. This study has not only given the researchers new insight into birds but a glimpse back into the evolution of flight.

New Discovery Sheds Light on Bird Evolution

June 25, 2009 by  
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Up until a few days ago it was a commonly held belief that modern birds evolved from theropod dinosaurs such as the tyrannosaurus or allosaurus. Now new evidence has been found in favour of the theory that birds evolved separately on a parallel path to dinosaurs.

The discovery may be new, but the evidence has been there all along. Simply put, it is virtually impossible for birds to have evolved from dinosaurs. Researchers at the Oregon State Univserity (OSU) in the US pinpointed the largest significant difference in their skeletal structures – their thigh bones – as proof of this fact. Up until now the relatively fixed position of the bird’s thigh bone and the role that it plays in keeping this creature alive has gone largely unnoticed. While virtually every other land animal has a moveable thigh bone, the bird’s thigh bone, or femur, is largely fixed, making them ‘knee runners’. What is most remarkable about this feature is that it is fundamental to the continued functioning of the animal; it is the fixed position of the femur and other bird bones that keeps their air-sac lung from collapsing when the bird inhales oxygen.

Research has revealed that warm-blooded birds need about 20 times more oxygen than do reptiles which are cold-blooded. As such, they have a unique lung structure which allows for a much higher rate of gaseous exchange and activity. It is this soft and delicate structure which is carefully protected by the fixed skeletal structures that surround the lungs.

According to Devon Quick, an OSU instructor of zoology, their unusual thigh complex and the way it supports the lungs is “fundamental to bird physiology.” Quick noted that “It’s really strange that no one realized this before. The position of the thigh bone and muscles in birds is critical to their lung function, which in turn is what gives them enough lung capacity for flight.” This only adds to other evidence that birds likely did not evolve from dinosaurs – such as the feathers, wings, bones and unique locomotion and lung system that is peculiar to birds – and supports the relatively new theory that they evolved separately on a parallel path to these extinct creatures.

Evolution

February 9, 2009 by  
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Scientists theorize that birds evolved from dinosaurs. This theory for the evolution of birds was brought about by the discovery of a fossil species possessing feathers. This fossil species called Archaeopteryx lithographica dates back to 150 million years ago and is thought to have evolved from dinosaurs called theropods. Archaeopteryx lithographica had two strong legs and walked as a bird does. Its skeleton was reptilian whilst it had the feathers of a bird. Recently, two other feathered dinosaur species were discovered in China. Scientists believe that this adds further proof to the theory of the evolution of birds from dinosaurs.

Other Scientist argue that birds evolved a long period of time before Archaeopteryx. They theorize that the evolution of birds occurred from 4 legged reptiles that died out with the dinosaurs. Such scientists believe that the actual ancestors of our birds today only appeared some 65 to 53 million years ago. This view is not popular amongst scientists though.

There are two theories as to why feathers would have developed in the evolution of birds. One is that because the ancestors of birds where becoming warm-blooded, they required the insulation of feathers. Another is that they develop due to a need for flight and gliding. Whilst many creatures have been and are able to fly, feather-powered flight is unique. This ability to fly gave birds the competitive edge as they could travel over greater distances and areas whilst seeking food. This also allowed them to live in places inaccessible to other animals.

Bird species have adapted to fit into various niches (a place and purpose in relation to the entire ecological community). They have developed instincts to feed, breed and migrate in a way that is species specific.

Birds today continue to adapt to the changing conditions of the world. Unfortunately, these changing conditions have seen many species become extinct. However, increasing awareness of the need to protect the environment and the animals who live in it may ensure that future generations will continue to enjoy these fascinating creatures.

Education

February 9, 2009 by  
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To be a true bird enthusiast you need to have a basic education on birds.

Here we cover everything from bird anatomy, conservation, the evolution of birds as well as extinct and rare birds. We hope to provide you with expert advice and opinions to help you become a better bird enthusiast and better bird owner.

Understanding the basic behavior of birds and their patterns, will also help you become a more accomplished bird watcher.

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