The study of birds is called ornithology, from the Greek ornis, bird, and logos, study. Ornithologists are biologists who specialize in studying birds. Aside from just being curious about how the world works, the study of birds can provide considerable information on how nature operates and how healthy our environment is. Birds are probably the most obvious and observed animal in our lives. No matter where you live, you can look outside and very soon see a bird. Being so common and obvious, birds have lent themselves to easy study and reflect what is happening in the environment.

Birds are highly sensitive to environmental changes, such as pollution, climate change, and loss of habitat. By monitoring bird populations, researchers can detect early warning signs of environmental degradation and gain insights into the overall health of ecosystems. If there are more or fewer birds, if the avifauna, the proportion of bird species, is changing, if birds are leaving on migration earlier than usual if there is an unusual number of deaths, something is happening in the environment that requires investigation. In the late 1950s, scientists noted that the populations of some birds, such as Bald Eagles, Brown Pelicans, and Peregrine Falcons, were declining. Further investigation showed that many of their eggs were not hatching. It turned out that DDT was preventing eggshells from depositing enough calcium to make the eggshells hard, and when the parents sat on the eggs, the eggs cracked. Further investigation of DDT showed that it was harmful to all kinds of living things – bees and other insects, mammals, birds, and humans and its use was banned in 1972.

Birds play a significant role in providing ecosystem services such as pollination, seed dispersal, and insect control which are essential for maintaining the balance of natural ecosystems. Birds also serve as vectors for various diseases, such as avian influenza and West Nile virus. Understanding their role in disease transmission is crucial for public health, and it can help prevent and manage potential outbreaks.

Observing bird flight has inspired human inventions, such as aircraft design and aerodynamics. The study of birds has often led to technological innovations and engineering insights. Japan's high-speed Shinkansen (bullet) trains that travel 300 mph were inspired by the streamlined shape of the kingfisher's beak. The design of some underwater vehicles takes inspiration from the aerodynamic shape and swimming techniques of birds that swim. Some advanced prosthetic limbs have been designed to emulate the flexible movements of bird wings, enabling more natural and efficient motion for users.

But ornithology is not limited to field observation; considerable work in the laboratory has been done on birds. Scientists, for example, discovered that birds' hearing does not decline with age as ours does, that they can see ultraviolet light as well as the light that is visible to us. We have learned that a  certain metal in the brain helps birds navigate on migration, that high flying birds have a hemoglobin that holds considerably more oxygen than mammalian oxygen does, and why some birds do not need to drink water as they metabolize all they need from the food they eat.

Overall, the scientific study of birds offers a wealth of knowledge about ecology, behavior, evolution, and environmental health, contributing to a better understanding of the natural world and the adaptations needed to survive in it. Ornithology also provides practical applications for conservation and sustainable environmental management.