Currently, there are 15 species and 48 subspecies of kingfishers known worldwide, distributed extensively across various regions.

The common kingfisher, named for its extensive distribution, is the most widely spread among the 15 species.

They are found throughout the Eurasian continent, as well as in Africa and Oceania.

The common kingfisher is not only common but also a highly intelligent bird. They exhibit exceptional fishing skills and fearlessness in the face of severe cold, displaying calm and wisdom.

As primarily fish-eating birds, common kingfishers are often seen by riversides or on rocks and vegetation in the water during the daytime. They become exceptionally quiet as soon as they land, with only their heads, capable of nearly 360-degree rotation, constantly scanning the water's surface.

Common kingfishers have extremely keen vision. While human vision is considered quite good, featuring contributions from both cone and rod cells, the fovea plays a significant role as well.

With a large number of visual nerve cells in the fovea, it enables us to see things more clearly. Common kingfishers possess two foveae, making their vision at least twice as sharp as ours. This allows them to see the movements of fish several meters underwater. Additionally, having two foveae compensates for the refraction caused by water and light, crucial for accurately locating the position and depth of fish.

However, excellent vision alone is not sufficient. Since common kingfishers dive underwater to catch fish, underwater vision and waterproof plumage are crucial. In this regard, common kingfishers excel effortlessly. Their entire plumage is waterproof, and a brief immersion in water leaves only a few droplets at the tips of their feathers, easily shaken off. Moreover, common kingfishers have a translucent nictitating membrane over their eyes.

While other bird species also have nictitating membranes, theirs are not highly transparent. The translucent membrane of common kingfishers closes upon diving, protecting their eyes without compromising visibility.

With outstanding vision and waterproof capabilities, common kingfishers can easily plunge into the water to catch fish. In addition to their waterproof primaries and secondaries, they also have down feathers with excellent insulating properties, akin to a down jacket, which preserves their body heat. Consequently, common kingfishers have become resident birds, capable of adapting to harsh winters and diving into cold waters to fish.

The fish caught by common kingfishers are always fresh, yet they lack teeth. So, how do they swallow fish without harming their digestive tract while the fish struggle? Common kingfishers have a technique. Typically, after catching a fish, they return to a high perch and grasp the fish's tail with their beak. Then, using their flexible necks, they repeatedly strike the fish until it becomes unconscious before swallowing it.

Apart from being their primary prey, fish also serve as tools for courtship among male common kingfishers. During the breeding season, common kingfishers first attract mates with their calls. Then comes the performance stage, where the male quickly dives underwater to catch a fish and presents it to the female. This act serves as a test of the male's suitability, and only upon passing it does the male gain mating rights.

Common kingfishers are beautiful and powerful birds with exceptional fishing abilities, sharp insight, and vigilant behavior, which has earned them the title of "common" kingfishers. Though once considered "common" due to their widespread distribution and abundance, they have become increasingly rare in many areas due to water pollution, drought, and intensified human activities.