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10.18: Bird Diversity

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    How are birds different?

    Not all birds look the same. They are obviously different in many ways. They come in all colors and sizes. They live in a variety of habitats. They eat a variety of foods.

    Diversity of Birds

    Turkey, hummingbird, penguin, parrot, owl and eagle. These are just some of the many different types of birds. If you just think about the birds in this list, the differences are striking. About 10,000 bird species belong to 29 different orders within the class Aves. They live and breed on all seven continents. The tropics are home to the greatest biodiversity of birds. The diversity among birds is striking. Birds can vary greatly in size and color. Some fly, some swim, some just walk or run. Some are savage carnivores, others are gentle herbivores. Some are low on the food chain, others are at the top.

    Birds live in a variety of different habitats. Birds that live in different habitats will encounter different foods and different predators. Birds can be carnivores (feeding on other animals), herbivores (feeding on plants), or generalists (feeding on a variety of foods). The lifestyle of the bird can affect what it looks like. For example, can you think of some examples of beaks that are adapted to the type of food a bird eats? Carnivorous birds include hawks, falcons, eagles, osprey, vultures and owls. Herbivorous birds include the goose, cockatoo and parrot. The American Crow is an example of a generalist. In addition, a specialist is a bird (or other animal) that is specially adapted to eat a certain food. An example of a specialist is a hummingbird, whose long, thin beak is excellent for reaching into flowers for nectar, but not very good for eating other foods.

    Waterfowl are birds that live on the water. These include ducks, geese, swans, and pelicans, to name a few. Landfowl are ground-feeding birds such as chickens and turkeys. Penguins are a group of flightless birds adapted for life in the water with flippers. Diurnal raptors are birds of prey that hunt during the day. These include falcons, eagles and hawks. Nocturnal raptors hunt during the night. These include various types of owls. Parrots are brightly colored and very intelligent. They are found in the tropics and include cockatoos, parrots, and parakeets.


    The size and shape of the beak is related to the food the bird eats and can vary greatly among different birds. Parrots have down-curved, hooked bills, which are well-adapted for cracking seeds and nuts (Figure below). Hummingbirds, on the other hand, have long, thin, pointed bills, which are adapted for getting the nectar out of flowers (Figure below). Hawks, eagles, falcons and owls have a sharp, hooked beak.

    The bills of a scarlet macaw and a hummingbird
    Figure \(\PageIndex{1}\): (left) The down-curved, hooked bill of a scarlet macaw, a large colorful parrot. (right) A long, thin and pointed bill of the hummingbird.


    Bird feet can also vary greatly among different birds. Some birds, such as gulls and terns and other waterfowl, have webbed feet used for swimming or floating (Figure below). Other birds, such as herons, gallinules, and rails, have four long spreading toes, which are adapted for walking delicately in the wetlands (Figure below). You can predict how the beaks and feet of birds will look depending on where they live and what type of food they eat. Flightless birds also have long legs that are adapted for running. Flightless birds include the ostrich and kiwi.

    Raptors have clawed feet. They also have strong legs. Hawks, eagles and falcons also have excellent vision and they hunt by sight. Owls, with excellent hearing, can hunt by that sense alone.

    The webbed feet of a seagull and the long toes of a gallinule
    Figure \(\PageIndex{2}\): (left) The webbed feet of a great black-backed gull. (right) The long spreading toes of an American purple gallinule.

    See Wild African Vulture Birds Scavage Bones of Dead Animals at and Ruby-Throated Hummingbird at for additional information.


    • Birds have beaks adapted for what foods they eat.
    • The feet of birds can be adapted for their specific habitat.

    Explore More

    Use the resources below to answer the questions that follow.

    Explore More I

    1. What are the penguins in the video feeding on?
    2. How do penguins store oxygen differently than other birds? How is this related to their lifestyle?
    3. Why do penguins control how much oxygen they carry in their lungs when they dive?

    Explore More II

    1. What is the fastest animal on the planet? How fast is this animal?
    2. How much g-force can a diving raptor experience? How would humans respond to these forces?


    1. What is a generalist? Name one bird that is a generalist.
    2. List three carnivorous birds.
    3. Give two examples of flightless birds.
    4. Give two examples of how a bird's beak is adapted to a specific food source.
    5. Give two examples of how a bird's feet are adapted to a specific environment.

    This page titled 10.18: Bird Diversity is shared under a CC BY-NC license and was authored, remixed, and/or curated by CK-12 Foundation via source content that was edited to the style and standards of the LibreTexts platform; a detailed edit history is available upon request.