Birds of prey, often called raptors, are formidable hunters in the animal kingdom. These birds are masters of the air, representing a diverse group of species found across nearly every continent. Their shared lifestyle as apex predators that hunt other animals from above is a testament to evolutionary adaptation. This success has led to a wide range of sizes and forms, from the smallest owls to the largest eagles. Understanding their diversity requires looking closely at what defines them and how scientists organize these specialists.
What Defines a Bird of Prey?
The classification of a bird as a raptor is based on physical adaptations suited for a predatory existence. These birds possess three distinct features that enable their hunting strategy: powerful talons, a hooked beak, and exceptionally keen eyesight. Raptors use their strong feet, tipped with sharp talons, to seize, carry, and kill their prey in a crushing grip. The size and curvature of the talons relate directly to the type of prey a species targets.
A highly curved, sharp-tipped beak provides the second signature feature. This specialized tool is used for tearing flesh into manageable pieces after the capture is made. For example, falcons utilize their beak to sever the spinal cord of their catch, while others use it for processing the carcass.
The third defining characteristic is superior vision, allowing them to spot small movements from great distances, often while soaring hundreds of feet in the air. Many diurnal raptors have eyesight far sharper than humans, acting like a “zoom lens” to pinpoint targets on the ground. Although “bird of prey” is an ecological description based on hunting behavior, it does not represent a single, unified taxonomic group, which complicates counting the total number of species.
Estimating the Global Species Count
Determining a single, fixed number for the world’s birds of prey is complicated due to ongoing scientific debates in taxonomy. Current global estimates generally range between 500 and 560 species, including both diurnal hunters (hawks and eagles) and nocturnal hunters (owls).
The variation in the species count often stems from differing scientific opinions on which groups to include or whether certain populations should be recognized as full species or subspecies. For example, some authorities place the seven species of New World vultures (condors and turkey vultures) in their own distinct order, Cathartiformes. Other classification systems, such as that used by the International Ornithological Committee (IOC), incorporate these seven species within the larger raptor order, Accipitriformes.
If the New World vultures are excluded, the count drops to around 482 to 490 species globally. Including all groups traditionally recognized as raptors—diurnal and nocturnal species—the number rises toward the higher end of the range, around 560 species. This dynamic number reflects the continuous work of genetic studies, which frequently lead to the “splitting” of one recognized species into two or more new species, or the “lumping” of several into one.
The Two Main Orders of Raptors
Raptors are primarily organized into major taxonomic groups that reflect their distinct evolutionary histories, despite their shared predatory traits. The vast majority of day-active birds of prey are contained within the Order Accipitriformes, which encompasses around 260 species. This highly diverse group includes the true hawks, eagles, kites, Old World vultures, the Osprey, and the Secretarybird.
The second major group of diurnal raptors is the Order Falconiformes, a smaller but globally distributed order consisting of falcons and caracaras. While falcons share the predatory lifestyle of the Accipitriformes, modern DNA evidence shows they are not closely related, instead linking them closer to parrots and songbirds. Falcons are known for their long, pointed wings and incredible speed, often hunting with high-speed dives.
The entire group of nocturnal birds of prey is classified into the Order Strigiformes, which contains all species of owls. This order is further divided into two families: the typical owls and the barn owls. Although owls hunt at night and possess specialized adaptations like silent flight, they complete the total count of birds recognized for their shared reliance on talons and hooked beaks for a carnivorous diet.