Birds of Prey
Birds of prey are birds that hunt for food primarily on the wing, using their keen senses, especially vision. They are defined as any bird that kills its prey with its talons. 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. The term "raptor" is derived from the Latin word "rapere" (meaning to seize or take by force) and may refer informally to all birds of prey, or specifically to the diurnal group.
The diurnal birds of prey are formally classified into five families:
- Accipitridae: hawks, eagles, buzzards, harriers, kites and Old World vultures
- Pandionidae: the Osprey (sometimes classified as subfamily Pandioninae of the previous family)
- Sagittariidae: the Secretary Bird
- Falconidae: falcons and caracaras
- Cathartidae: New world vultures including condors.
The nocturnal birds of prey - the owls - are classified separately as members of two extant families of the order Strigiformes:
- Strigidae: (typical owls)
- Tytonidae: (barn and bay owls).
The observation that otherwise unrelated bird groups may perform similar ecological roles and bear striking morphological similarities to one another is explained largely by the idea of convergent evolution.
The common names for various birds of prey are based on structure but many of the traditional names do not reflect the evolutionary relationships between the groups.
Types of Birds of Prey
The common names for various birds of prey are based on structure but many of the traditional names do not reflect the evolutionary relationships between the groups.
Variations in shape and size
* Eagles tend to be large birds with long, broad wings and massive feet. Booted eagles have legs and feet feathered to the toes and build very large stick nests.
* Ospreys, a single species found worldwide that specializes in catching fish, and builds large stick nests.
* Kites have long wings and relatively weak legs. They spend much of their time soaring. They will take live vertebrate prey but mostly feed on insects or even carrion.
* The true Hawks are medium-sized birds of prey that usually belong to the genus Accipiter (see below). They are mainly woodland birds that hunt by sudden dashes from a concealed perch. They usually have long tails for tight steering.
* Buzzards are medium-large raptors with robust bodies and broad wings, or, alternatively, any bird of the genus Buteo (also commonly known as "hawks" in North America).
* Harriers are large, slender hawk-like birds with long tails and long thin legs. Most use a combination of keen eyesight and hearing to hunt small vertebrates, gliding on their long broad wings and circling low over grasslands and marshes.
* Vultures are carrion-eating raptors of two distinct biological families, each occurring in only the Eastern Hemisphere (Accipitridae) or the Western (Cathartidae). Members of both groups have heads either partly or fully devoid of feathers.
* Falcons are small to medium-size birds of prey with long pointed wings. Unlike most other raptors, they belong to the Falconidae, rather than the Accipitridae. Many are particularly swift flyers. Instead of building their own nests, falcons appropriate old nests of other birds, but sometimes they lay their eggs on cliff ledges or in tree hollows. Caracaras are a distinct subgroup of the Falconidae unique to the New World, and most common in the Neotropics - their broad wings, naked faces and appetites of a generalist suggest some level of convergence with either the Buteos or the vulturine birds, or both.
* Owls are variable-sized, typically night-specialized hunting birds. They fly with extreamly little audible turbulance due to special feather structure and have particularly acute hearing.
Diurnality
Diurnality is an animal behavior characterized by activity during the day and sleeping at night. Animals that are not diurnal might be nocturnal (active at night) or crepuscular (active primarily during twilight, i.e., at dusk and dawn). Many animal species are diurnal, including many mammals, insects, lizards and birds. The diurnal pattern is often controlled internally by the circadian rhythm (endogenous rhythm) of the animal. In some animals, especially insects, external patterns of the environment control the activity (exogenous rhythms, as opposed to patterns inherent in the habitat).
Some mainly nocturnal or crepuscular animals have been domesticated as pets and have changed into diurnal animals to coincide with the cycle of human life. Examples are pet dogs and cats, which are derived from the wolf and the wild cat, respectively. However, these animals may exhibit their species' original behavior when they are born feral. Other animals have been forced from their normal cycle to an alternate one as a means of avoiding predators, such as beavers becoming nocturnal creatures after extended predation by mankind.
Many plants are also diurnal or nocturnal, depending on the time period when the most effective pollinators, i.e., insects, visit the plant. For example, as most angiosperm species of flower are visited by many various insects, the flower adapts its phenology to the most effective pollinators in order to ensure proper reproduction and longevity of the species. Thus, the effectiveness of relative diurnal or nocturnal species of insects affects the diurnal or nocturnal nature of the plants they pollinate, causing in some instances an adjustment of the opening and closing cycles of the plants.