Kingfishers are a group of small to medium-sized brightly colored birds in the family Alcedinidae. They are found worldwide, mostly in the tropical regions. Kingfishers get their name from their specialized hunting behavior – diving into water to catch fish. However, kingfishers are opportunistic feeders and eat a variety of prey besides fish.
Insects
Insects make up a large part of the diet of most kingfisher species when fish are scarce. Kingfishers will hawk flying insects like dragonflies, grasshoppers, butterflies, bees, wasps, flies, and moths in flight. They will also glean stationary insects like beetles, caterpillars, cicadas, crickets, spiders, centipedes, and millipedes from vegetation. The hooked bill of kingfishers allows them to snatch insects rapidly. In some species like the laughing kookaburra, insects can make up over 50% of the total food intake.
Preferred Insect Prey
The preferred insect prey depends on habitat and availability. Kingfishers found near water favor dragonflies, damselflies, mayflies, water striders, and diving beetles. Forest kingfishers target butterflies, moths, beetles, grasshoppers, cicadas, crickets, and spiders. Kingfishers in open habitats prefer preying on flying insects like flies, bees, wasps, and winged termites.
Hunting Technique
Kingfishers employ different techniques to hunt insects. To catch flying insects, they hawk from an exposed perch scanning for prey visually and snatch them out of the air. For gleaning stationary insects, kingfishers move quickly through branches using short flights interspersed with brief pauses to locate camouflaged or hidden insects. The long bill is used to probe crevices and dig into wood or soil to expose concealed insects.
Small Vertebrates
Kingfishers supplement their diet with small vertebrates like fish fry, tadpoles, frogs, toads, newts, small reptiles, rodents, and young birds when available. These provide a nutritious source of protein and fat for kingfishers.
Fish Fry and Tadpoles
Kingfishers that frequent aquatic habitats feed extensively on fish fry and tadpoles that are more easily caught than adult fish. Tadpoles are swallowed whole while fish fry may be manipulated first to align head first for swallowing.
Frogs and Toads
Kingfishers opportunistically prey on frogs and toads. The prey is usually swallowed whole and alive. Toads with toxic skin secretions are rubbed on the ground or repeatedly dipped in water before swallowing to remove the toxic coating.
Lizards and Small Snakes
Small lizards like anoles and swift-running skinks are captured by kingfishers. Quick reflexes allow them to grab small snakes like garter snakes, thread snakes, and worm snakes. These prey items are beaten against a perch before swallowing to subdue them.
Rodents and Small Birds
Some larger kingfisher species like laughing kookaburras prey on mice, voles, shrews, small squirrels, and juvenile birds snatched from nests. Kookaburras may cooperate to hunt swift flying avian prey like swallows, swifts, and bee-eaters in intricate cooperative displays.
Crustaceans
Kingfishers that frequent brackish and saltwater habitats feed on small crustaceans like crabs, shrimp, isopods, and amphipods. These are captured in shallow water and often swallowed whole.
Crabs
Small crabs that live in mangrove swamps, tidal pools, and mudflats are preyed upon by kingfishers. They use their bills to flip over camouflaged crabs to expose their vulnerable undersides.
Shrimp
Kingfishers plunge into shallow water to grab small shrimp that lurk near the edges of estuaries and beaches. The shrimp are visible as they disturb sediment while moving.
Isopods and Amphipods
Beachcombing kingfishers probe into sand and pebbles near the surf to capture burrowing isopods and amphipods. Isopods washed up after high tide are also eaten.
Other Invertebrates
Kingfishers prey on a wide range of invertebrates other than insects and crustaceans depending on opportunities. These include snails, earthworms, leeches, crayfish, crabs, and even jellyfish.
Snails
Small water snails and land snails are hammered against perches to crack the hard shells before swallowing.
Earthworms
Earthworms exposed during rain or plowing are snapped up from the ground. Kingfishers vibrate their heads to dislodge any clinging soil from the worms before consumption.
Leeches and Crayfish
Leeches are picked off vegetation near water. Large kingfishers are able to swallow small crayfish whole.
Jellyfish
Beached jellyfish are consumed opportunistically by beachcombing kingfishers. They may shake jellyfish to remove clinging sand before swallowing.
Fruit
Kingfishers are primarily carnivores but occasionally supplement their diet with fruit, especially in tropical regions when insects and small vertebrates are scarce.
Figs
Kingfishers often feed on figs from strangler figs that grow around tree trunks. The fruits that drop to the ground are snatched up.
Berries
Kingfishers perch at fruiting shrubs to consume soft berries and fruits. Favorites include currants, elderberries, grapes, mulberries and pepperberries.
Wild Dates
Oil palm fruits and wild dates from palms provide a carbohydrate source for kingfishers in tropical habitats.
Nectar
A few specialist species like the brown-hooded kingfisher have uniquely adapted to consume nectar from flowers, in addition to insects. Their brush-tipped tubular tongue allows them to drink nectar while perched.
Preferred Flowers
The brown-hooded kingfisher favors flowers of the kapok, eucalyptus, madras thorn and silk cotton tree. They use nectar as an energy source when insect prey is scarce.
Feeding Adaptations
This nectar feeding adaptation allows the brown-hooded kingfisher to exploit a niche without competition from other birds in its range. The nectar does not provide complete nutrition though, so insects are still the primary prey.
Carrion
Kingfishers are primarily hunters of live prey but occasionally scavenge on dead animals. Small amounts of carrion provide an easy meal. Kingfishers have been observed scavenging dead fish, frogs, rodents, and even other birds.
Fish and Frogs
Dead fish and frogs that have washed up on shore are eaten by beach patrolling kingfishers. This provides a source of food with minimal effort.
Carrion Feeding Advantage
Eating carrion allows kingfishers to obtain animal protein without expending energy on hunting. However, they do not rely primarily on scavenging due to risks of bacterial contamination.
Coconuts
An unusual food source utilized by the Micronesian kingfisher is coconut flesh. Using their strong beaks, they drill holes through the coconut husk to access the nutritious coconut flesh and coconut water inside.
Specialized Feeding Adaptation
The Micronesian kingfisher is the only species with this specialized adaptation to access and consume coconut flesh. It provides a reliable source of fat and protein in its island habitats.
Dietary Supplement
Coconuts are only a supplemental food source though. The Micronesian kingfisher still gets the bulk of its nutrition from insects, crabs, lizards, and small fish.
Seeds
Though primarily carnivorous, some kingfishers opportunistically eat seeds from grasses, sedges, and fruiting plants. These are usually unintended ingestions when catching insect prey.
Grass and Sedge Seeds
Seeds from grasses and sedges are inadvertently consumed when kingfishers grab insects and spiders from dense grassy vegetation. The hard seeds usually pass undamaged through their digestive tract.
Fruit Seeds
Kingfishers that feed on soft fruits often swallow the small seeds. Fig seeds are commonly consumed when feeding on ripe figs.
Conclusion
In summary, kingfishers are resourceful and opportunistic foragers. While fish make up a large portion of their diet, they will feed on any abundant small prey. Their diverse prey includes insects, crustaceans, small vertebrates, invertebrates, fruit, nectar, carrion, coconuts, and even seeds. Kingfishers are adept at utilizing the niche food resources available in their habitats.