Birds of prey are birds that hunt for food primarily on the wing, using their keen senses, especially vision. They are defined as birds that primarily hunt vertebrates, including other birds. Their talons and beaks tend to be relatively large, powerful and adapted for tearing and/or piercing flesh. In most cases, the females are considerably larger than the males. Taken literally the term "bird of prey" has a wide meaning that includes many birds that hunt and feed on animals and also birds that eat very small insects. In ornithology, and the definition used here, the term has a narrower meaning for birds that have very good eyesight for finding food, strong feet for holding food, and a strong curved beak for tearing flesh. Most birds of prey also have strong curved talons for catching or killing prey. Birds of prey generally prey on vertebrates, which are usually quite large relative to the size of the bird. Most also eat carrion at least occasionally and the vultures and condors eat carrion as their main food source. By way of an example, the narrower definition excludes storks and gulls, which can eat quite large fish, partly because these birds catch and kill prey entirely with their beaks and similarly bird-eating skuas, fish-eating penguins, and vertebrate-eating kookaburras are excluded. I have not included Storks, Gulls or Kookaburras in this book, I wanted to concentrate more on the larger Birds of prey.

There are twenty four diurnal raptor and ten owl species native to Australia. Whilst owls are not taxonomically classed with the diurnal raptors, or birds of prey, they share many of the physiological characteristics, requirements and traits of diurnal raptors. They have hooked bills, are carnivorous and, most significantly, use their powerful feet to catch and kill their prey. They fill an equivalent niche in the environment, and for all practical intents and purposes may be considered "raptorial" by nature.

The family Accipitridae is a family of birds of prey and include hawks, eagles, kites, harriers and Old World vultures. In the USA there are some 27 species of Birds of prey, though many are declining in numbers, especially in California.

The remote region of India's high Himalayas is home to some of the biggest birds of prey in Asia including the Himalayan Griffon Vulture, Lammergier and even the mighty Golden Eagle. It took years to find out why India's three vulture species -- the long-billed, slender-billed and oriental white-backed vulture -- were dying off. It turned out were feeding on dead cattle and other livestock that had been treated with an anti-inflammatory drug called diclofenac. It was discovered in 2004 that diclofenac sends vultures into renal failure. When we were in India we hunted far and wide to find some, we did. Shortly after the vulture photos I took, India banned the veterinary form of diclofenac, but vets and farmers just switched to using the version of the drug intended for humans. This is a last-ditch effort to save the three vulture species from extinction. The mass vulture die-offs have had terrible consequences throughout India. With no vultures to eat cattle carcasses but they are still just dumped when the cows die. Twenty common North American birds of prey have more than halved in number in the last four decades, while in Asia, the millions of white-rumped vultures which once filled the skies have crashed by 99.9 per cent and the species is now critically endangered. Birds provide an accurate and easy-to-read environmental barometer. When will we learn?