With upwards of 10,000 species of birds in the world, I wanted to find out how diverse birds are. From the smallest sparrow to the largest eagle, the diversity between species of birds is incredible. Find out why birds are one of the most diverse animal groups on Earth.
The diversity of birds can be seen in their different habitats, geographical locations, the shape of their bills and their feet and toes. Their size, colors, diet and different ways of flying are also very different.
If you want to find out more about why birds are so diverse then please read on.
Different Species and Orders
There are roughly 10,000 species of birds in the world, with estimates of almost one thousand in North America.
Birds can be found in many different habitats from tundra to deserts and almost everywhere in between. For a bird to live in a specific habitat, they have to be able to survive against predators and be able to find food.
Birds live in a wide variety of habitats including tundra, forests, deserts, seawater and freshwater, rainforests, and mountainous regions.
The size of a bird affects the size of their range, and this also affects their population size. Large species are usually less abundant than small species. If their range size is also small, then this will also affect their population size.
There are very few species of large birds that have small ranges as they prefer a large range. However, small birds do not always stick to smaller ranges, and can often be found in large ranges.
The beak of a bird varies depending on the type of food that they eat. Birds with a less-varied diet will have a bill shaped to get to their preferred food.
Finches have a wedge-shaped bill allowing them to crack seeds, using a nutcracker motion. Parrots can crack the shell of a nut using their powerful bills, before pulling out the nut with the down-curved tip.
Toucans have large bills which they use to cut off fruit from the tree, before slicing it into manageable chunks.
Some birds such as the godwit have a long up-curved bill. They use this to pick up aquatic prey. Whimbrels have a down-cured bill that they use to dig in the sand for crabs, mollusks, and fish.
Crossbills feed on spruce and pine cones which they pry open with their bills. Their upper and lower mandibles cross making this an easy task.
Grosbeaks have stout bills which they use to eat seeds. The bill of a woodpecker is straight which allows them to get to ants by chiseling at the tree. Nuthatches have long bills that allow them to get into crevices.
Species of bird such as nightjars and swifts have a short bill which allows them to catch insects while in flight. Orioles use their bills in a variety of ways. They can snatch caterpillars and other insects from trees, but also use their bill to stab fruit. They then open their mouth which cuts into the fruit, allowing them to drink from it.
Feet And Legs
Further diversification between birds can easily be seen in their legs and feet. Birds’ legs and feet are different according to the functions they need to perform.
Birds toes often point forwards and backward. Some species of woodpeckers have two that face forwards and two that face backward. This allows them to hang onto the sides of trees easier.
Most have three facing forward and one pointing backward, but this depends on the species. However, some species do not have a backward-facing toe. Birds can have 2, 3, 4, or 5 toes.
Some birds walk on their toes (digitigrade), however, others will walk flat on their feet, with their heel on the ground.
Birds can use their feet to walk, run, hop climb, swim, steer, perch, catch and kill prey, and scratch, among others.
Some birds have webbed feet, such as ducks, geese, swans, although this is generally limited to aquatic birds. The webbed feet help them to swim and steer when in the water.
Some species such as coots and grebes have lobed feet. These are generally long and help the bird walk on soft, uneven surfaces. These stiff flaps are found along both sides of the toes.
All birds have claws on the end of their toes. The forelimbs on a bird are the wings.
Birds range in size from the smallest bird in North America, the Calliope hummingbird, to the largest, the California Condor. The Californian condor has a wingspan up to 9 1/2 feet and weighs up to 23 pounds. The Calliope hummingbird is tiny at 3 inches (8 cm) long and weighs 0.1 oz.
The body size determines the life history of the bird. Larger species tend to live longer and breed later in life. They also have a longer breeding cycle and have fewer young. Some large birds do not start breeding until they are 10 years old and may lay just one egg with an incubation period of 2 months.
This is in stark contrast to some smaller birds which start to breed in their first year and lay up to 12 eggs. Smaller birds also generally have a lower incubation period than large birds, typically a couple of weeks, and may have two breeding periods in a year. This inevitably leads to a higher population of small birds than large birds.
Although large species generally live longer than smaller species, there are some exceptions to this. Tiny hummingbirds only lay two eggs, whereas an ostrich can lay up to 10.
With such a huge range of species, there should be no surprise that almost every color can be seen on a bird. Birds have a wide diversity of patterns and colors on their plumage.
The colors are used in various ways and can be used to aid in courtship or to display a threat. Colored plumage can also be used as camouflage from prey and predators. Generally, only the parts of the feathers that can be seen are brightly colored, with those concealed being dull.
Colors on feathers are produced by pigments called melanins and lipochromes. These two pigments produce different colors on the feathers.
Lipochromes produce reds, oranges, yellows, greens, and blues. Melanins produce darker colors such as blacks, browns, reddish-browns but also some yellows. Colors are sometimes related to the diet of the bird with crows and ravens needing plenty of riboflavin in their diet to achieve their color. These pigments can also protect the bird from ultraviolet rays from the sun.
There is another diversity within the colors of birds. Colors are either iridescent or non-iridescent. Non-iridescent colors can be seen from any angle, but iridescent colors such as those on hummingbirds can only be seen from certain angles.
Although birds of different species have a diversity of colors, birds of the same species can also have different colors depending on where they live. Birds that live in shady areas may be different colors from those that live in areas of high sun. This is due to some colors fading in the sun.
The flight is an adaptation that birds use to move around. Birds do not all fly in the same manner however, using several different methods.
We are used to seeing birds flap their wings. In this method of flight, birds flap their wings up and down to propel themselves through the air. On the upstroke, the wings are held so that the wingtip moves closer to the body. On the downstroke, however, the wings move downward parallel to the body.
The downstroke generates thrust and allows the bird to fly straight and level, whereas the upstroke can provide lift in some circumstances.
The amount of times the wings are flapped depends on the species and size of the bird. Hummingbirds can beat their wings 80 times a second, whereas some herons will flap their wings twice in a second.
Although all birds that can fly use their wings in this manner, the diversity of flight in birds can be seen by species that use thermal currents to soar and glide. Some species of birds save energy by riding these air currents to great heights. By locking their wings, the thermal air currents allow them to glide without using energy flapping their wings.
Soaring is generally only used by larger birds such as birds of prey, sea birds such as albatrosses and gulls, although ravens, storks, and herons also use this method of flight.
Birds can use the thermals to reach heights before gliding off to new territory. Once they reach a new thermal, they can begin to climb again. Soaring is used to search for a few reasons including hunting for food and during migration.
Whereas soaring is reserved for large bird species, hovering is a means of flight that is done by some of the smallest birds. Hummingbirds hover so that they can reach areas that would be difficult to reach, such as plants that would collapse even under their tiny weight.
By keeping their wings fully extended and flapping very fast, the hummingbird can support their weight without propelling themselves forward. They do this by slanting the body upwards, causing the flight feathers to beat horizontally. They then flap their wings in a figure of eight, with the downstroke being a forward stroke and the upstroke a downwards stroke.
Birds such as the blue tit use a bounding flight effect. In doing this, they interchange moments of flapping their wings into a state where they keep their wings directly against the sides of their bodies and following the path they are going.
The undulating flight is similar, whereas it is moments of gliding followed by flapping. Both of these methods can be used to save energy in flight.
There is another method that some birds also use to save energy when flying. This can be seen when you watch a bird that flies close to the ground. The ground helps to reduce drag on the wings, helping to save energy.
Although we think of birds as animals that use their wings to fly there are over 60 species that cannot fly at all, further diversifying birds from each other
Flightless birds are not just limited to a specific order and many orders also include birds that can fly.
Another way to see how diverse birds are is to study their diet. Birds can eat a huge variety of foods.
The diet of a bird will generally depend on the species and size of the bird.
Larger birds such as birds of prey will eat other birds, mammals, rodents, frogs, fish, and crustaceans.
Smaller birds may eat insects, earthworms, snails, fruit and berries, spiders, seeds, other birds, mammals, rodents, frogs, fish, crustaceans, plants.
However, the diet of a bird does depend on its species and habitat.