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22nd July 2020 - Wings and flight

 

 

Perhaps only our most avid followers will have noticed that back in June we had a bird anatomy theme on social media. Well I got a bit carried away with my research and ended up having way too much to fit into one or two social media posts. Once I started reading the many different adaptations of different bird species wings, my fascination was captured! So, I thought I would put my efforts to good use a blog post to share with you.  

Birds' wings are strong, light and flexible and they all share the same pattern (primary, secondary, and tertiary flight feathers, lesser and man coverts ...... hmmm I can see another blog post here!). But the shape and size all vary, meaning different bird species have been able to specialise in different types of flight.  

For many birds, being able to pursue prey or escape predators over quite short distances is much more important than being able to stay in the air for a long time. A broad, rounded wing is best for this type of flight, because it gives good acceleration and can be finely adjusted for steering.  

Chaffinch

Flight makes enormous demands on a bird's body but the initial take-off requires all the power it can produce. Pigeons have strong wing muscles making up a third of their weight which enable it to take off rapidly and accelerate up 50mph. Their wings are broad for manoeuvrability but with a pointed tip for speed.

Birds that live in woodlands need short rounded wings so that they can turn suddenly to avoid obstacles. Finches and tits are hunted by many predators, they rarely fly far, but they can constantly veer and turn on the wing  

In general birds that fly rapidly and powerfully have pointed wings. Think of swifts and peregrine falcons. Their wings are shaped for flapping flight as opposed to soaring. The swift is also just one of a number of birds which only lands to breed and its slender curved wings are completely adapted for continuous use.  

Brent Geese

Geese travel enormous distances each year to breed in the arctic tundra. Their flight is not fast but they are able to maintain this speed for many hours without stopping. Goose wings are long and broad to provide the lift needed to keep birds weighing up to 5kg airborne.

When a bird flaps its wings it uses about 15 times as much energy as when it is sitting still. Some larger birds have evolved to soar and glide in order to save energy. They harness the power of the sun or the wind to keep them in the air. Other birds like kestrel have evolved to "hover" and can keep still in the air by beating their wings non-stop, just as a swimmer treads water to stay afloat.  

Heavy birds of prey like the buzzard soar on thermals. They only need to use flapping flight to get from one thermal to the next. Their broad flight feathers provide lift as they soar.

Gulls slender pointed wings enable them to glide on updraughts. The lift generated by updraughts is enough to support birds as heavy as the great black-backed gull, which weighs over 2kg. Their narrow wings provide lift without too much drag.

Buzzard

When I started delving into this I was fascinated by the huge variability of birds wings. Considering the huge variability of birds themselves it isn't actually that surprising. Birds inhabit every continent, and are among the most diverse vertebrate groups on Earth. The smallest flying bird is the bee hummingbird at only 1.6g and the heaviest flying bird is the kori bustard at 18kg. The arctic tern migrates a whopping 44,000miles (the longest migration of any animal in the world) whilst New Zealands's national bird, the kiwi, doesn't fly at all. Some birds, like the ostrich, have evolved to run and other, like the penguin, to swim. You get the idea birds and their wings are amazing!

Ranger Karima 

N.B. many of the fascinating facts from this blog post were taken from "Bird" an Eyewitness guide written by David Burnie.