What is the Difference between New World and Old World Vultures?
Vultures are all large, carrion-eating birds.  For years, it was believed that all vultures were raptors, members of the order Falconiformes.  In 1994, however, it was discovered that the vultures inhabiting the American continents share a common ancestor with storks and ibises.  Now, American vultures, or New World vultures, are recognized as Ciconiiformes, in the family Cathartidae.  European, African, and Asian vultures are recognized as Old World vultures (family Accipitridae, subfamily Aegypiinae).  There are 15 species of Old World Vultures and 7 Species of New World Vultures.

          General Information
I'm sure you've gazed at one of those noble, graceful figures soaring in the sky on a mild day... Well, what you are seeing is probably not a hawk.  It is a vulture.  Vultures are one of very few creatures capable of soaring for hours at a time.  And it is effortless.  For years, superstitious individuals have claimed that the sight of soaring vultures is a sure signal that a dead animal can be found nearby.  This is not true.  Vultures are highly intelligent creatures who love to play as much as humans.  When a vulture discovers a thermal (warm pocket of air), the bird is able to hold its wings motionless, and allow the warm air to carry it in large, sweeping circles, toward the sky. 
          Ugly Animal?
The vulture's bald head is one feature that appears revolting to many people, but it is a brilliant physiological property that allows the creature to plunge into all sorts of carcasses, and come out clean.  Without feathers to serve as a habitat for all the bacteria that infests their meals, vultures soar through their lives disease-free.  After eating, vultures can often be seen perched in the heat of the sun.  Here, whatever has managed to cling to the few bits of fuzz on their head will be baked off once and for all.
          Many of the behavioral traits of the vulture have brought it considerable (and unfair) attention as an unsanitary creature.  However, each habit of the vulture is an adaptation, evolved to help it survive under the conditions in which it lives.  First of all, a diet of dead and decaying flesh would turn our stomachs inside out.  But think of how our landscape would look without the help of the vulture.  Serving as nature's janitors, these wonderful birds fly about, stomaching the most revolting of cuisine, and ridding our ecosystem of maggots and disease-carrying viruses in the process.  With 100 times the botulism of a human, the stomach of a vulture can digest meat in advanced stages of decay, a favor to every other creature in the world. 

The Vultures of the World