One winter day, I watched a Sharp-Shinned Hawk unsuccessfully try to catch one of the sparrows and house finches at my bird feeders. I was fascinated by how the birds quieted down and flew off in many directions before the hawk even reached the feeder. That is how I could tell a predator was around, by the reaction of the birds.
If you think about it, raptors aren’t the only “birds of prey”. Swallows, warblers and chimney swifts are among other birds that catch, eat or feed insects to their young. But a few characteristics make birds of prey different.
The common name “raptor” comes from the Latin words “robber” and “seize”. Raptors bodies are adapted for seizing prey.
These swift fliers eat and hunt animals such as small birds, mice, rats, snakes, lizards, frogs and fish.
All raptors have a strong, compact body, heads that are generally round, a short sharp-hooked beak, strong feet with sharp talons, keen eyesight, and a carnivorous diet.
There are two kinds of raptors diurnal or day-fliers which include hawks, falcons, vultures, ospreys and eagles. Nocturnal raptors include the owls.
Raptors have forward directed eyes and sharp vision to spot prey from a distance.
Raptors have three eyelids! They have a top and bottom eyelid plus a third, transparent eyelid which closes laterally across the eye. This special eyelid is called a nictitating membrane and is used to:
- keep the eyes moist,
- protect the eyes during flight, and
- protect the eyes when feeding themselves or their young.
When humans close their eyes to blink or sleep the upper eyelid closes. Depending on the species, raptors may close the top eyelid, the bottom eyelid, or both.
An additional form of eye protection in many raptors is a bony shield, called the superciliary ridge, that projects above the eye. This ridge acts like a visor for protection from the sun and also protects the eyes from injury while hunting. It also gives raptors a menacing appearance.
Raptors have short legs and long toes with bent sharp claws.The feet and beaks are designed for catching and ripping open the skin of prey.
Raptors range in size from the Elf Owl which is smaller than a Robin, to the largest bird in North American, the California Condor. In almost all raptor species, females are larger than males.
Raptors colors are subdued with plummages of tans, grays, and browns. None of the raptors are brightly colored. In most species adult and immature juvenile plumages are very difficult to tell apart. This can make identification a real challenge.
Raptors make simple calls. Usually the calls consist of high pitched and harsh repeated notes. They don’t sing. Kites and buzzards tend to be the most vocal.
In one of the bird watching workshops I attended, I learned that the high-pitched call of eagles in television commercials are not actually eagles but the Red-tailed hawk. The squeaky calls of eagles aren’t dramatic enough.
Raptors can live a long time. Bald Eagles can live over twenty years. Smaller raptors like kestrels can live up to ten years. Once a bird reaches adulthood, it will probably live a long time as long as habitats and food supplies are relatively healthy and abundant.
Raptors are found on every continent except Antarctica. The greatest number of species is found in the tropical rainforests of Central and South America. Raptors live in urban, suburban and rural areas. The Sharp-shinned Hawk, I wrote about earlier, lives in my neighborhood on the edge of large, very urban, Philadelphia. It flew right into my small backyard.
It just proves you don’t have to go to distance lands to see something magnificent.
Information in italics from, ” General Raptor Facts”, Bureau of Land Management, http://www.blm.gov/id/st/en/prog/blm_special_areas/birds_of_prey_nca/links/general_raptor_facts.html, accessed 22 November 2011.