Prairie Warbler Portrait

This is a wonderful video courtesy of © Lang Elliott

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Bird Flight

Basic mechanics of bird flight

Here are the explanations of the main mode of locomotion used by most of the world’s bird species.

Lift

The fundamentals of bird flight are similar to those of aircraft. Lift force is produced by the action of air flow on the wing, which is an airfoil. The lift force occurs because the air has a lower pressure just above the wing and higher pressure below.

Gliding

When gliding, both birds and gliders obtain both a vertical and a forward force from their wings. This is possible because the lift force is generated at right angles to the air flow, which in gliding flight comes from slightly below the horizontal (because the bird is descending). The lift force, therefore, has a forward component that counteracts drag.

Flapping

When a bird flaps, as opposed to gliding, its wings continue to develop lift as before, but the lift is rotated forward to provide thrust, which counteracts drag and increases its speed, which has the effect of also increasing lift to counteract its weight, allowing it to maintain height or to climb. Flapping involves two stages: the down-stroke, which provides the majority of the thrust, and the up-stroke, which can also (depending on the bird’s wings) provide some thrust. At each up-stroke the wing is slightly folded inwards to reduce upward resistance. Birds change the angle of attack between the up-stroke and the down-stroke of their wings. During the down-stroke the angle of attack is increased, and is decreased during the up-stroke.

Drag

Apart from its weight, there are three major drag forces that impede a bird’s aerial flight: frictional drag (caused by the friction of air and body surfaces), form drag (due to frontal area of the bird, also known as pressure drag), and lift-induced drag (caused by the wingtip vortices). These forces are reduced by streamlining the bird’s body and wings.

Photographs are © H.J. Ruiz – Avian 101

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Andes Art

Years ago in one of my trips to Lima, Peru. I bought some souvenirs made by people from the Andes. This woman selling  handmade trinkets to tourists near a beautiful park, she offer me some small bead bracelets she had for sale. I wasn’t interested. Just by curiosity I asked her what else did she have? Then she reluctantly pulled  a smaller bag with what she described hand work from her husband that workes in the mines, he picks up pieces of different minerals he finds and then he makes souvenirs during his off days in order to have an extra income, support for his family.

I saw what they were and I was quite surprised by the craftsmanship and artistic little sculptures.

They’re beautiful figures of birds made of several different minerals.

The wooden parts I added for display purposes (3”x 3”)

Aren’t they lovely? I have a habit to keep mementos from places I visit. These were birds, by pure coincidence. Isn’t it ironic?

“Seems like birds were always part of my life, without me being aware of it!”

Text and photographs © H.J.Ruiz – Avian 101

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More birds, More seeds!

I can see more birds coming to eat at the dishes I placed on my deck’s table lately. Our weather is improving also, it feels a bit warmer and we have sunshine early. Of course that it gets cold at night but not too bad.

I shot a picture of my cat VanGogh watching the birds from the kitchen glass door. He gets all excited watching the birds come and go.

I’m still waiting for warmer days so I can start going out and fixing my feeders and bird houses. Then go shooting more pictures.

Field Sparrow

VanGogh, my cat

Text and photographs © H.J. Ruiz – Avian101

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