Wednesday, September 15, 2010

Wing Shape

As you observe the birds around you when you walk through the forest, sit in your yard, or visit the World Bird Sanctuary, you will notice that bird wings come in many shapes and sizes.
 Red-tailed Hawk in flight (photo by Gay Schroer)
You can tell a great deal about a bird’s lifestyle just by looking at the shape of its wings.  The variation in wing form is due to the different uses each bird species has for its wings.  Some birds need to soar for long periods of time.  Others need to use their wings for very rapid flight.  Still others need wings that allow for agility so they can evade predators or avoid running into trees.
  Turkey Vulture in flight (photo by Gay Schtoer)
The next time you are outside, see if you can spot one of the many turkey vultures found in our area.  You will notice that they flap their wings very rarely. Using very broad wings with long, slotted primaries, they can ride on the rising thermals.  That way, they will expend as little energy as possible as they search for carrion below.

Millenium, a Peregrin Falcon in her juvenile plumage - note how long and pointed her wings are (photo by Gay Schroer) 
In contrast, falcons can’t just cruise the region in search of ready-to-eat meat.  If a falcon had broad wings like a vulture, it would fly too slowly to catch its prey.  If a falcon wants to catch, for example, a pigeon, it needs long, narrow, pointed wings capable of high speed flight.  The peregrine falcon’s wing shape allows it to reach record dive speeds of 175 mph! 
  A wild Cooper's Hawk-note it's shorter rounded wing shape in contrast to the falcon's (photo by Cathy Spahn)
Raptors in the accipiter family, such as the sharp-shinned hawk and the Cooper’s hawk have short, rounded wings. Their wing shape gives them the agility they need to maneuver through their forest homes without flying into trees

http://www.stanford.edu/group/stanfordbirds/text/essays/Soaring.html

Submitted by Leah Sainz, World Bird Sanctuary Naturalist

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