Bird Parts

Adaptations are the way birds of prey have changed over time so that they can get enough food, mate, and successfully live in the world.  We chose a couple of adaptations so that you could see how a bird of prey's body helps it to actually get food. Beaks     Birds of prey always use their beaks to get food.   Most of the time, beaks are used to rip their food up into smaller pieces so that they can eat it.  Birds of prey have beaks that are curved down.  They grab their prey, puncture it with their beak while they hold it with their talons, and yank on the meat until they pull it out to eat.  These birds will sometimes use their beaks to help them kill their prey.  For example, owls will use their beaks to put lots of pressure on the animal to kill it.  Kestrels and falcons use a slit in their beak to break the necks of their prey.     How they capture and eat their prey depends a lot on the size and shape of their beak.  For example, vultures eat prey that is already dead.  With their long and skinny beaks, they can grab meat that is between bones left from other vultures and meat-eating animals.  They don’t have to hurry to ‘dinner’ because there will still be food left that other birds of prey couldn’t reach.     Another example is owls.  Many owls swallow their prey in one piece, throwing up what they can’t digest later.  Their beaks are small which is okay because they don’t have to tear up their food before eating it, like other raptors do.  They get small prey so they don't need a large beak for that, either.     Different raptors use their beaks to catch different things.  Most birds of prey eat small mammals.  If you ever have the chance, look at a bird of prey’s beak and make a guess at what it eats.  You may be surprised how close your guess is. Beaks:  Click on the link below each bird to see what they eat.  Do they eat large or small animals?  Do they kill or tear with their beaks?  Do they have to pry out their food?  How does their beak shape help? Black Vulture Steller's Sea-eagle Snail Kite American Kestrel Golden Eagle   Gyrfalcon

Feet

   Birds have feet that are used in some way for their survival.  Most of the time birds use their feet to walk on.  An example is robins that use their feet to walk around to find worms in the ground.  They have to be on the ground so that they can feel and hear the worms.  They would not live without this food.
    A bird of prey depends on its feet and talons even more than a robin would.  Most raptors use their feet to capture, hold, and kill their prey so their feet and talons need to be very strong.  A few raptors, like vultures, don’t kill their prey.  Their prey is already dead so their legs and feet don’t have to be strong enough to kill anything.
    A raptor’s legs are usually covered with feathers down to its ankle.  The feathers are used for warmth and to help them fly quieter.  The bird that flies quieter is a more successful hunter.  The muscles that make it possible for the bird to perch and grab prey are at the top of the leg.  Raptors have the ability to ‘lock’ their feet around a branch, relax their muscles, and actually stay firmly in place.
    A bird of prey has scaly skin on its feet.  Each foot has three toes that face forward and one that sticks out of the back of the foot.  The strongest, or gripping toes, are the back one and the inside front one.  The outside ones are used for balance.  At the end of each toe is a claw, or talon.  Sometimes the claws make it hard for the bird to walk.  An example of this is the Osprey.  They catch fish so their talons are curved or bent so much that they have a hard time walking on the ground.  Since they are hunting fish, not being able to walk around on the ground is not a big problem.  Birds of prey have legs, feet and talons that are equipped to hunt whatever they like to eat like the Osprey.   Snake hunting birds have shorter toes so that the snake can’t wiggle its way out of its grip. 
    Owls have weaker feet but sharper talons because they don’t use them to tear apart their prey, but rather to puncture their prey.  Owls have feathered legs and feet to keep them warm.  They also leave less of their body open to bites by prey.  This is different from most raptors that have ‘bare’ feet.   Most raptors kill and tear apart their prey and end up with blood on their feet and talons.  Owls don’t have this problem because they don’t use their feet in the same way.  The bottom of an owl’s foot is bumpy so that prey can be gripped better.  When owls are perched on a branch they can move there outer toe to the back because of a special joint they have.  Owls are the only raptors that can do this.
    When we visited Mr. Sliker, a falconer, we were able to see talons up close.  Their grip is amazing!  They can put about 1400 pounds of pressure on their prey when humans are capable of only 400.  Talons can pierce right through the body of a rodent!  Talons are used for hunting, climbing, and perching. No matter where you sit, talons are scary looking. 

Feathers

    We thought that feathers were all the same, but that isn’t true.  There are different kinds of feathers that are used for different jobs.

	Down feathers:  These feathers are used to keep the birds warm and, with owls, help them fly quietly.
	Flight feathers:  These are on the wings and tail.  The tail feathers help the bird steer and stop.  The other flight feathers are fanned and moved as the bird flies.
	Contour feathers:  These are used to cover the bird, keep it warm, and to mold the shape of the body so that air flows easily over it.

    When we visited Mr. Sliker, we learned that feathers can determine whether the raptor is a silent flier, like an owl, or one that can be heard, like a Peregrine Falcon. Raptors that can be heard while flying have stiff feathers which are strong enough to handle the wind resistance when they dive.  This resistance is caused by the speed of the dive.  Owls have feathers with soft, fluffy edges so they can’t be heard while flying in the dark.  Then they can swoop down on their prey unnoticed.
    Feathers are made of keratin which is the same thing that claws and fingernails are made from. Birds have more feathers in the winter than the summer to keep them warmer.  Once a year, feathers will fall off and new ones will take their place.  This is called molting.  Molting takes a few months to do and all of the feathers are dropped and others are grown in their place.  It is like baby teeth that you lose.  You grow adult teeth to replace them.  It’s the same with feathers—only it happens once a year.
    Feathers are used for more than flying.  Males use their feathers to attract a female for mating and they can be used to camouflage the birds when they are nesting.  They can also help sounds get into an owl’s ears.
    Birds get dirty and their feathers sometimes get messed up.  When this happens, they use their beaks and talons to ‘preen’, or clean and straighten out their feathers. 

Wings

    Wings come in many different shapes and sizes, such as an owl, whose wings are normally large and rounded.  It takes powerful muscles to allow the bird to fly, and the muscles react differently to do different things.  To flap up, the wings have to separate and allow air to come through.  To flap down, the feathers close, not allowing any air to come through. 
    If you were able to see a raptor swoop down through a forest of trees to grab its prey on the ground, you would be amazed at how flexible the wings are.  As wind currents change or the bird has to turn to avoid a tree, he bends down, to veer left or right- all while he is flying unbelievably fast.  They can use their wings and feathers to speed up or slow down, turn or hover.  Their tail feathers are used like a ship’s rudder, steering left and right.

Works Cited:

Burnie, David.  Bird.  London: DK, 1988.

Davies, Nicola.  Birds.  Boston: Kingfisher, 2003.

Green, Jen.  Birds.  Milwaukee: Gareth Stevens, 1998.

Krautwurst, Terry.  “Raptors, the sky masters.”  Mother Earth News.  Aug/Sep2007 Issue 223, p52-57.

Laubach, Christyna.  Raptor!  North Adams, MA:  Storey Books, 2002.     

Lewis, Deane P.  “Owl’s beak or bill.”  23 Oct. 2007.  <http://www.owlpages.com/articles.php?section

=Owl+Physiology&title=Beak>.

Lewis, Deane.  “Owl feathers and flight.”  23 Oct. 2007.  <http://www.owlpages.com/articles.php?section=Owl+Physiology&title=Feathers>.

Lloyd, Glenys.  Birds of prey.  NY:  Grosset & Dunlap, 1970.

"Monocular vision." Wikipedia, The Free Encyclopedia. 31 Mar 2008. <http://en.wikipedia.org/w/index.php?title=Monocular_vision&oldid=200749249>.

Owl talons.  23 Oct. 2007.  <http://www.owlpages.com/articles.php?section=Owl+Physiology&title=Talons>.

Raptor eyes, feet, wings & beaks.   22 Dec. 2007. <http://www.hawkandowl.org/page103.html>.