Birds are warm-blooded tetrapod vertebrates (ie, endotherms) that have very distinctive characteristics that separate them from other animals. Their ancestors were a group of theropod dinosaurs that inhabited Earth during the Jurassic, 150-200 million years ago. They are the most diverse vertebrates, with some 10,000 current species. They inhabit all environments on the planet, finding them from cold areas of the poles, to deserts and aquatic environments. There are species as small as some hummingbirds, to large species such as the ostrich.
Since there is such a diversity of birds, in this article on our site, we will tell you what these animals have in common, that is, all the characteristics of birdsand its most surprising details.
Plumage, the most singular characteristic of birds
Although not all bird species can fly, most do so thanks to the streamlined shape of their bodies and wings. This ability allowed them to colonize all kinds of habitats that other animals would be unable to reach. Bird feathers have an intricate structure and have evolved from simple beginnings in pre-avian dinosaurs to their modern form over millions of years. Thus, today we can find great differences in the 10,000 species that exist in the world.
Each type of feather varies according to the region of the body where it is found and according to its shape, and this varies in each species, since the feathersnot only fulfill the function of flight, but also serve for the following :
- Partner selection.
- During nesting.
- Recognition of conspecifics (ie, individuals of the same species).
- Thermoregulation of the body, since in aquatic birds their plumage traps air bubbles that prevent the bird from getting wet during dives.
- Camouflage.
Main characteristics of birds
Within the characteristics of birds, the following stand out:
The flight of the birds
Thanks to the shape of their wings, birds can perform anything from spectacular glides to undertaking extremely long journeys, in the case of migratory birds. Wings have developed differently in each group of birds, for example:
- Featherless Birds: in the case of penguins, they lack feathers and their wings are fin-shaped, since they are adapted for swimming.
- Birds with reduced feathers: in other cases, they are reduced, such as ostriches, chickens or partridges.
- Birds with rudimentary feathers: Other species, such as kiwi, have rudimentary wings and feathers similar in structure to hair.
On the other hand, in flying species the wings are highly developed and depending on their lifestyle, they have different shapes:
- Rounded and wide: in species that inhabit closed environments.
- Pointed and narrow: in fast-flying birds such as swallows.
- Long, narrow wings: present in birds such as seagulls, which hover over water.
- Finger-like feathers: also in species such as vultures, finger-like feathers are seen on the tips of the wings, this allows them to glide at great heights, taking advantage of hot air columns in mountainous areas, for example.
However, there are also flightless birds, as we explain in this other article on Flightless Birds - Characteristics and 10 examples.
The migration of birds
Birds are able to carry out long flights during migrations, which are regular and synchronized, and occur due to seasonal changes where birds move from wintering areas in the south to summer areas in the north, for example, to seek better food conditions to feed their young during the breeding season.
During this season, migration also allows them to find better nesting grounds and raise their chicks. On the other hand, this process helps them maintain homeostasis (internal balance of the body), because these movements allow them to avoid extreme climates. However, birds that do not migrate are called residents, and have other adaptations to face unfavorable times.
There are several ways in which birds orient themselves during their migrations, many studies have shown that they use the sun to find their way. Navigation also includes detection of magnetic fields, use of smell and visual landmarks.
The skeleton of birds
They have a peculiarity in their bones, and it is the presence of holes (in flying species) that are filled with air, but with great resistance which in turn gives it lightness. On the other hand, they have different degrees of fusion in different areas of the body, such as the skull bones that do not have sutures. The vertebral column, in turn, presents variations, since it has a greater number of vertebrae in the neck, which generates great flexibility. The last posterior vertebrae are also fused with the pelvis and form the synsacrum. On the other hand, they have flattened ribs and a keel-shaped sternum, which serves for the insertion of the flight muscles. They have feet with four toes, and depending on their arrangement, they have different names:
- Anisodactyls: it is the most common among birds, with three fingers forward and one backward.
- Syndactyls: fused toes, third and fourth toes, like Kingfishers.
- Zygodactyls: typical of arboreal birds, such as woodpeckers or toucans, with two toes forward (toes 2 and 3) and two behind (fingers 1 and 4).
- Pamprodactyls: arrangement in which the four toes point forward. Characteristic of the swifts (Apodidae), where the nail of the first finger is used to hang, since these birds cannot perch or walk.
- Heterodactyls: Same as zygodactyly, only here fingers 3 and 4 point forward and fingers 1 and 2 point back. It is typical of trogoniformes, such as quetzals.
Other characteristics of birds
Other characteristics of birds are the following:
- Highly developed sense of vision: they have very large orbitals (where the eyeballs are housed) and voluminous eyes, and this is flight related. Their visual acuity, especially in some species such as eagles, is up to three times better than that of other animals, including humans.
- Poor sense of smell: Although in many species, such as some scavengers, kiwis, albatrosses and petrels, smell is highly developed and allows them to locate their prey.
- Well-developed hearing: which allows certain species to orient themselves in the dark because they are adapted for echolocation.
- Horny beaks: that is, they have a keratin structure, and their shape will be directly related to the type of food they have. On the one hand, there are beaks adapted to sipping nectar from flowers, there are wide and robust ones to be able to open grains and seeds. On the other hand, there are filtering beaks that allow them to feed in the mud or in flooded areas, there are also spear-shaped ones to be able to fish. Some species have them firm and pointed to be able to bite on the wood and others, with the shape of a hook that allows them to hunt prey.
- Syrinx: it is the vocal organ of birds, and in the same way as the vocal cords in humans, it allows them to emit vocalizations and melodious songs in some species to be able to communicate.
- Reproduction: Birds reproduce by internal fertilization and lay eggs with a hard calcareous covering.
- Matching: they can be monogamous, that is, they maintain a single partner during the entire reproductive season (or even longer, or in consecutive years), or being polygamous and having several partners.
- Nidification: they lay their eggs in nests built for that purpose and where both parents or only one can participate in its construction. The chicks can be altricial, that is, they are born devoid of feathers, so the parents invest a lot of time in feeding and caring for them; or they can be born precocious, and in which case they leave the nest before and the care by the parents lasts a short time.
