Ornithology is a branch of zoology that deals with the study of birds. The branch Ornithology, not only deals with the study of anatomy and physiology of birds but also it deals with studying the environment, habitat, evolution, and several other aspects of birdlife. The term Ornithology has derived from a Latin term named ‘ornithologia’ dated back in the 16th century. The study of birds has also helped in gaining knowledge in several aspects of biology ranging from evolution to differentiation in species as well. 


We have come across birds through many legends and stories such as Aesop’s fables of the 6th century. We can say that the study of birds started much earlier in prehistoric times. This is evident through the inscriptions on stones and drawings on stones which proves how important were birds even in the early era. Birds have been amongst the most important source of food in the past as well as the present.

Aristotle was the first person before Darwin times, who took up the work to distinguish between 500 species of birds. The system of classification described by Aristotle was one of the earliest and most important in describing the scientific taxonomy. His main classification was based on animals with blood and animals without blood followed by vertebrates( animals with the spinal cord ) and invertebrates( animals without spinal cord ). According to him the ‘Ornithes’ that is the Greek name for birds, are animals that have blood and lay eggs. They have 2 legs and are distinguished from other animals by feathers and have beak instead of teeth and they are included under the egg-bearing tetrapods.  

Until the 17th century, the birds were described more in folklore and had more of a symbolic significance. During the year 1676-1678, the encyclopedia that was named the ‘ornithology of Francis Willughby’ came into existence that rejected the ancient folklore regarding the birds and started describing the biology of birds instead. In the year 1691, Rays ‘wisdom of God’ described the study of birds in two sections which are:

  • Nomenclature and systematics which was inspired by ornithology

  • Natural history 

Charles Darwin mentioned over 600 bird species and discussed around 100 ornithological topics. The scientific order of ornithology originated after the theory of natural selection by Darwin was accepted in the 20th century. Approximately, around 300 species are named after Darwinii. One of the important works of Darwin includes Finches, also called as Darwin’s Finches. These are a group of 26 species of passerine birds. This includes half of all bird species and is differentiated from other birds by the arrangement of their toes. They are also called as perching birds or songbirds. Darwins Finches are a good example of animal evolution.

Motive to Study Ornithology 

There are approximately 9000 to 9500 species birds that are still living and almost 23 to 24 orders of birds. The study of Ornithology as a subject helps us to understand the environment of birds, have an idea regarding the endangered species of the birds, and also gives a brief idea regarding the human past. Ornithology helps us to study the bony structures of the birds to understand their habitat and migration needs and thus help in knowing the population of the modern birds. Ornithology also helps us to understand the process of evolution and helps in the differentiation of species.

Endangered species are those which are on the verge of extinction. Some of the varieties of the endangered species of birds include:

  • The Giant Ibis: This is as of now considered to be the most endangered variety of birds. This is a huge variety of birds that are natives of northern Cambodia that are almost a meter in height and weigh around 4-5kgs. As per the records it is claimed that around 90-100 mating pairs are left in the wild. 

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  • California Condor: These are native to the Sierra Nevada mountains and Mono Basin and are among the critically endangered species. This has a wingspan of approximately 3m that is considered as the widest among any North American bird. It can easily weigh around 10 -12 kgs and is considered as a scavenger bird.

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  • Forest Owlet: This variety of birds were believed to be extinct until 1997 when they were rediscovered in Maharashtra, India. The population of this species of bird is estimated to be around 80-350 individuals. 

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  • Philippines Eagle: This is a majestic bird that can grow around a meter in height and 6-8 kgs in weight. This is considered as the largest Eagle in the world considering its majestic height. The current population in the wild is somewhere around 150-450 adults.

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One of the several approaches towards the study of birds included the collection of eggs. This is called as Oology. This branch of Ornithology gives a brief idea regarding the bird’s nest and breeding techniques as well. Though nowadays this method is considered illegal in many countries. 

During earlier times when high-resolution cameras and binoculars were not available, the study of birds was difficult. Either the birds were shot to death or their eggs were collected for examining. In this method usually, the whole clutch of eggs is taken since eggs will get rotten if the contents are still inside. Hence, the contents are removed by making a tiny hole without breaking the rest of the egg. This is also called egg blowing. Freshly laid eggs are easy to blow when compared to the eggs in which the development is already started. 

The collection of the egg was also a hobby in the 20th century. Usually, large eggs were collected for trading purposes and also for egg decorating.

Migration and Mating Behaviours 

The mating behaviors of birds are different than that of the other animals. While some birds attract the mates through song while some include dancing. Some variety of birds can produce no sound at all but they can display different movements and behaviors to attract their mate. There are few species of birds that come together only for copulation, while some species connect a mate bond for whole life, and some form pair only for an incubation period. The parental care amongst the birds is also different. While few varieties give a lot of care to the offspring and few do not care much. 

Birds are said to live in different habitat at different times of the year. For this, they migrate from one place to another that can be as far as 3000-6000 km away. Many of the variety of birds are said to cover hundreds of km in a single flight while few take rest in between their flights before reaching the destination. 

Birds use a variety of geographical landmarks to determine the direction of their migration and flight like star position, solar cues, wind directions, etc. even the sound plays an important factor to guide them to their destination. 

Field and Laboratory Study of Birds 

The study of birds in the field was possible after the development of high-resolution cameras. Photography with high power cameras enables us to record even the minutest feature and detail of the bird. When the bird is caught in hand, the first thing recorded is the measurement and then the other features are noted such as the shape of the beak, the color, its feathers, its toes, etc. The skull provides the details regarding the age and sex of the bird. Blood samples are collected to study the DNA which helps us to understand genetics and also trace it back to the ancestors to understand the pattern of evolution. Hormonal conditions are noted to understand the physiology and pathology of birds to know better about the diseases in birds and to relate it medically with humans by enhancing the development of new vaccines and medicines for various diseases in humans. This proves helpful in creating vaccines for different types of viruses. Marking the bird for future references is an important criterion in the field study. 

When it comes to some endangered varieties of birds, the use of camera traps plays a helpful role in following the bird to know much about their life, their breeding, and habitat. 

There are many characteristics of the birds that cannot be studied and noted in the field. Thus, a laboratory study of such species is done for further evaluation and to record the details of the birds. The blood and feather samples collected from the birds during the field study can be further evaluated in the laboratory. This helps us to understand the physiological and behavioral aspects of the birds better. Some characteristics of a few varieties of birds like singing and intelligence are studied and better understood in the laboratory only. Studying the physiology of the bird helps us determine the migration in birds by understanding what helps them in navigation for migration. Noting the temperature and eyesight also helps in this regard. 

Most of the vaccines for viruses are tested first on poultry to know the effectiveness. The first attenuated vaccine was developed for fowl cholera in the year 1878 by the famous Louis Pasteur. 

Classification of Birds 

The first and basic classification includes the

  • Modern Birds: These are also called as the Neornithes. These include almost all the living birds and their descendants. They are characterized by a developed sternum, not so long tail, these have no teeth and instead have beaks, modified forelimbs into wings. These are warm-blooded and the skull has a single condyle. Lungs have extended air sacs to help them maintain breathing during flights. The body is covered with feathers. The DNA has proven the modern birds of being evolved in the middle and late cretaceous era. Birds have a high metabolic rate and these birds have evolved themselves according to the habitat they survive in. some birds who live in an aquatic environment have evolved themselves into swimming as well.

  • Reptile Like Birds: These birds were also called as Archaeornites and considered as the first primitive group of birds that are now extinct. These birds have the non-avian dinosaurs as their ancestors. The characteristic features of the reptile-like birds include wings that are clawed, they had a tail which was bony and long, unlike the modern birds that have short tails. And few birds had teeth along with beaks.

FAQ (Frequently Asked Questions)

1. What is the Importance of the Ornithologists?

Ans: With time the make-up of birds ranging from physical to genetic change. Birds have been evolving over a period of time. Studying the characteristics of birds and their bony structures help in understanding the habitat, lifecycle, modern bird population, and their physiology and pathology. This concept can be studied under branch Ornithology and hence it proves the importance of Ornithologists. 

2. What are the Characteristics of Aves?

Ans: Birds belong to the class Aves. They are warm-blooded animals with their body covered by feathers. They have beaks instead of teeth. The forelimbs are modified into wings and the hind limbs into toes that are clawed. They have well developed digestive and respiratory system which has an additional air sac to help them breathe better during flight sessions. They have a high metabolic rate.  

3. What is the Relation Between Dinosaurs and Modern Birds?

Ans: Some fossil shreds of evidence prove that modern birds are evolved from Dinosaurs. They belong to the subgroup of theropod dinosaurs. More precisely they belong to the group of Maniraptora. Maniraptora included birds and non-avian dinosaurs of the Jurassic period. Maniraptorans had characteristics that included long arms, three-fingered hands, and semi lunate shaped wrist. Most of the studies belonging to the 21st-century state that the Maniraptorans were more of omnivorous creatures.

4. When Did the Ornithology Grow to Popularity?

Ans: The use of field glasses and telescopes for the observation of birds came into existence after the 1830s. This is when the study of birds or Ornithology gained much popularity. This method for the observation of birds was introduced by J.Dovaston. Later after the 1900s, the interest for bird watching increased all over the globe.