Kingfisher: the electric blue hunter
Quietly perched over a slow-moving river on a summer morning, a bird is hunting. Tilting its head from side to side, it assesses the movements of a small shoal of sticklebacks in the water below. Carefully it adjusts its position, sidestepping along a narrow twig. It seemingly bobs its head to gauge the exact position of its chosen meal. Then, without hesitation or warning, there is a flash of electric blue as it dives head first into the water. A split second later, it emerges triumphantly, a small fish in its beak. A kingfisher has caught another meal.
In late summer, the kingfisher, Alcedo atthis, is busy finding food not just for itself, but for a brood of chicks. The diet is principally small fish, with minnows and sticklebacks the preferred food. The ideal prey is just under an inch (2.5cm) in length but they will take fish up to 3in (8cm). They also feed opportunistically on aquatic insects, as well as small amphibians such as newts. Occasionally, terrestrial insects such as dragonflies are eaten.
Feeding is performed by diving into the water to catch prey in the beak. To stop the fish or insect escaping, it is held tight with the aid of small ridges in the beak. Dives start from overhanging branches, or following a brief hover when there is no suitable place to perch. The eye cone cell of a bird’s retina contains an oil droplet which may contain carotenoid pigments to help to enhance colour vision and remove glare. This helps the bird to cut through the reflection of the water’s surface, enabling it to spot a meal.
Plunges are propelled by a few wingbeats before the wings are folded down along the sides of the bird as it enters the water. The eyes are protected by a translucent third eyelid, allowing the bird to see while under water. At the same time, an egg-shaped lens in the eye allows binocular vision under water. This lets the kingfisher judge distances so it can capture its prey.
Emerging beak first, strong wingbeats propel the bird from the water to land on a nearby perch. Once settled, the bird knocks larger fish against its perching stick to ensure they are dead. Smaller prey are usually killed by the tight grip of the bill. Knocking a stickleback has the added benefit of relaxing its spines to stop it becoming trapped as it is swallowed. The bird then slowly moves the fish round until it is positioned headfirst for consumption. Several times a day, a small pellet of indigestible fish bones and other material is regurgitated.
Courtship and mating
The brood the kingfisher is feeding at this time of year is likely to be its second. Most pairs of birds have two, sometimes three broods. The breeding season starts early in April, so by July, the first chicks will have fledged and be hunting for themselves,
Courtship begins with aerial chasing, always near a prospective nest site. The male bird chases a female along the river from branch to branch with both birds calling to each other. The male may dive into the river many times to show off his hunting skill.
To impress the female, he excavates numerous nest holes, each between 18-36in (45-90cm) in length. Most often these tunnels are in the steep banks of meandering rivers. They can also be in the underside of upturned trees or lakeside banks. He creates the holes by flying at the bank and driving in his strong bill. Once the female decides a particular hole is suitable, she may help with the excavation.
Inside, the tunnel rises gradually from the outer hole, with an enlarged chamber at the end for the nest. The nest is most usually unlined, with the eggs laid onto the mud of the chamber bottom. Once construction is finished, courtship feeding begins. The male offers fish to the female outside the nest before mating occurs. He continues to catch fish for his mate until all of the eggs have been laid. They often mate after each time he gives her fish.
Each clutch has six to seven white, glossy eggs almost spherical in shape. Incubation takes between 19-21 days with the male and female taking turns on the nest. Changeovers can occur every 3-4 hours, giving each parent a chance to feed. The female often sits on the eggs during the night. One or two eggs may fail if the parent birds do not cover them fully during incubation.
Once hatched, both parents feed the young for between 23-27 days. Initially, feeding occurs once every one to two hours. It then increases steadily to almost every 15 minutes in the last days before the young emerge from the nest. Parent birds may stop feeding once the chicks are large enough to fledge. They sit outside the nest on a perch with a fish, calling to the young to tempt them out of the nest.
After fledging, the parent birds often feed the youngsters for two days outside the nest. Once they are ready to fend for themselves the young are usually chased from the adults’ territory to find their own before winter arrives.
Kingfishers are found most frequently on lowland, slow-moving rivers, open fresh water and wetland habitats. They are only absent in the highest mountainous regions of Britain. Here the rivers are too fast flowing and lack suitable cover for fishing.
To attract kingfishers, there needs to be an ample supply of small fish all year round. These birds need to eat at least 60 per cent of their body weight in fish every day to survive. Overhanging vegetation provides perches to hunt from.
Areas with tall vegetation are often preferred because of the large shadows cast over the water. This cuts down on surface reflection, helping the birds to see the small fish in the water below. They can be found feeding along canals and under road bridges, where the shade provides ideal conditions for them. There also need to be suitable nesting sites on steep banks.
There are approximately 3,800-4,600 breeding pairs in Britain. This reflects a steady decline from the 1970s when the population was approximately 18 per cent higher at 5,000-5,600.
The reduction in numbers is mostly as a result of increased river pollution. Kingfishers also face threats from both predation and disturbance while nesting. Nest holes that have accessible ledges make it easy for predators such as stoats and weasels to gain access. Human disturbance comes from machinery or work for river management.
Additional threats to breeding success include the climatic conditions. Heavy and consistent rainfall makes it difficult for adult birds to find food for themselves and their young. Survival rates are low for fledglings in their first year, often as a result of starvation. This is due to lack of hunting experience or poor habitat, sometimes a result of being pushed from prime locations by a dominant adult. Herons and sparrowhawks also take young and inexperienced birds. If they survive that first year, the average lifespan of an adult is between five to seven years.
During the winter, kingfishers are mainly solitary. The male may hold onto his summer breeding territory over the winter with the female being found in a neighbouring territory. Most do not breed for life, although it is not unknown for a pair to stay together over following years.
Territories are usually made up of at least 1/2mile (1km) of river, but can be up to three miles (5km) wide. Any nearby watercourse that provides good fishing opportunities will also be protected as part of an individual’s territory. The male protects his territory by driving off any challenging party with aerial chases. Occasionally fights occur, in which one bird will grab the other by the bill, trying to force them under the water.
If conditions are poor in the colder months, kingfishers may stray into neighbouring areas in search of better feeding opportunities. Then, as spring approaches, they start a new quest for a mate.
Hidden under foliage as it watches for prey in the water below, often the only time a kingfisher is seen is when it dives. Then there is a flash of brilliant blue, a splash – and the bird is gone again. Their exotic appearance, incredible hunting prowess and subtle nature, however, make even this fleeting vision one that is truly enchanting.
Distinguishing the sexes
Males and females can be easily distinguished by their bills. The males have an entirely black beak from base to tip. The females have a red lower bill from the base to the centre. In July and August, juveniles from earlier broods can be seen. They are identified by a small white tip to the ends of their bills. The pointed bill of the adult is approximately 13/4in (4cm) in length, from tip to the base of the skull.
The bright blue upper parts of the head and back are complemented with chestnut orange underparts. At close range the head shows a complex pattern of blue and orange, with white visible under the base of the bill and behind the eye.
Weighing just over 1oz (34-39g), adult kingfishers are approximately 6in (16-17cm) in length, with a wingspan of 10in (24-26cm). They fly fast, at approximately 10-20mph up and down the river, usually two or three feet above the water. Their unique call is an unmistakable high pitched, piercing tone of a ‘ch(r)ee’ shrill.
The kingfisher, Alcedo atthis, takes its name from the Latin halcyon and the Greek halkyonk, plus Atthis, a beautiful woman from the isle of Lesbos. In the past, kingfishers were associated with powers relating to the weather. In Latin, the halcyon was a mythical bird that had a nest of fish bones on the water. While incubating its eggs, it was said no storm would rise. This period was believed to start seven days before the winter solstice, and last until seven days after.
Kingfishers were also made into weathercocks. A mummified bird would be suspended by a thread and its beak was said to face the direction of the prominent wind. The practice is referred to by Shakespeare, in King Lear. “Bring oil to fire, snow to their colder moods/Renege, affirm, and turn their halcyon beaks/With every gale and vary of their masters.”
Words: Tom Mason Photography: Alamy