Alcedo Atthis Bengalensis
Geographic Range
Alcedo atthis is found throughout Europe and Asia as far east as Japan. They are also found in Africa, south of the Sahara. Common kingfishers are year long residents in their southern habitats, while northern populations travel south during the winter to escape freezing water. Alcedo atthis is the only species of kingfisher in much of its European range.
Habitat
Common kingfishers are found on the shores of lakes, ponds, streams, and in wetlands. They have even been known to fish in brackish waters, especially during the winter months, when other bodies of water may be frozen.
Physical Description
Common kingfishers are reknowned for their iridescent blue plumage. The entire upper portion of the bird: wings, back, and head are completely blue. The underbelly and a small patch underneath the eyes are rich chestnut. The throat and a small part of the side of the neck is bright white. They have small red feet. Their beaks are long, sharp and strong for the purpose of catching and holding prey. Males and females are very similar except for their beaks. A male’s beak is jet black, while the lower half of a female’s beak is chestnut. Juvenile’s are slightly more green and duller than adults.
Reproduction
Mating is the only time that Alcedo atthis individuals are not solitary. At the beginning of the mating season, males will chase females through the trees, producing a loud whistle. Common kingfishers will find a new mate each year. Mating only occurs in the warmer months of the year, starting in April and ending sometimes as late as October.
In about mid-March nesting begins. The male and female work together to dig a hole into a bank along a water source. Common kingfishers prefer steep banks. The holes are of various depths and are dug into various types of soil. Usually a hole between 15 and 30 cm long is dug, but on occasion some as deep as 1.2 meters have been discovered. They may nest in clay, rock, or sandy ground. Nests also vary in the distance they are above the water, with the distance varying from 0.5 to 37 meters above the water level.
Both parents will raise and feed the young. However, the female will do most of the work. Common kingfishers will brood 2 to 3 clutches a year. These clutches consist usually of 6 or 7 eggs, but there may be as many as 10.
Both males and females help to raise the young. For 19-21 days they incubate the eggs. Both will incubate during the day, only the female at night. Both have active roles in brooding and feeding the young, but the female does most of the work. One parent will hunt, then return with a fish exactly the right size for the young, they will also hold it by the tail so that the young can swallow the fish head first. When the young are able, they will eagerly wait at the opening of the burrow to be fed. After 23-27 days the young fledge and emerge from the nest.
Lifespan/Longevity
Common kingfishers can live for as long as 15 years. The average lifespan is 7 years. However, the first months of development are the most dangerous with only 50% of the young surviving to adulthood.
Behavior
Common kingfishers are very territorial, as are all kingfishers (Alcedinidae). This is mainly because they must eat around 60% of their body weight each day. They will even defend their area from their mates and offspring. For most of the year individuals are solitary, roosting in heavy cover next to their favorite hunting spot. If another kingfisher enters its territory, both birds will sit on a perch some distance from each other and engage in territorial displays. This usually entails displaying beaks and plumage. Occasional fights also occur, where a bird will grab the other's beak and try to hold them under water.
The flight of common kingfishers is very fast, which makes their wings look like a blue haze. Common kingfishers can be seen flitting about waterways and wetlands.
Communication and Perception
Common kingfishers have advanced eyesight, with the ability to polarize light, reducing the reflection of light off of water. They also learn to compensate for refraction, allowing them to catch prey more effectively. Common kingfishers communicate vocally. They are well known for their long, trilling call which sounds like a repetition of “chee”. When mating, a male will whistle loudly to a female and chase her above and through the trees. In a dive for prey, a membrane covers their eyes and they rely solely on touch to know when to snap their jaws shut.
Food Habits
Common kingfishers hunt for prey from a perch above the water. Perches may be several centimeters to several meters above the water. When they see potential prey, they dive into the water, grab the prey, and fly back out. Sometimes when a perch is unavailable they will hover above the water to search for prey. After catching a fish, common kingfishers will hold the prey by its tail, and whack it against the perch. This stuns or kills the prey, which is particularly important when eating fish with spines. After consuming a fish it will regurgitate a pellet of indigestible bone.
Common kingfishers eat mostly small fish, making up 60-67% of their diet. They may also eat small arthropods, such as Gammarus fasciatus. Crustacea consist of 5-33% of their diet. Common kingfishers have also been known to eat crabs and other small marine animals during the winter.
Predation
Common kingfishers have few natural predators as adults. However, because they are high on the food chain, they are susceptible to the effects of bioaccumulation, the concentration of pollutants as they climb the food chain. Nestlings may be preyed on by snakes and other ground-dwelling predators, but kingfishers are aggressive birds and do defend their young against predators.
Ecosystem Roles
Kingfishers are a good indicator of ecosystem health. Because kingfishers eat small aquatic animals, they are severely effected by toxins in the water. A strong kingfisher population usually means a healthy enviroment. Common kingfishers are important predators on small fish in freshwater habitats throughout their range.