Of the many birds that frequent our chalk streams, the brightly-plumed kingfisher is perhaps the most iconic. The species we have here in the UK is the Eurasian kingfisher – one of more than 100 such species worldwide, including Australia’s laughing kookaburra. Also called the "common kingfisher" or "river kingfisher", this dazzling bird makes for an unforgettable sighting.

Despite being resident on many of our chalk streams, the kingfisher often goes unseen. This is partly due to its swift flight; encounters typically consist of a vibrant streak whizzing away into the distance. But even when perched, its diminutive size (a mere 16cm long, on average) means you'll need sharp eyes to pick it out. Your best bet is to watch the water and listen for a series of short, high-pitched whistles - this could be a kingfisher about to take off, or one already on the move.

Amazingly, the kingfisher's best-known feature - its electric blue plumage - is an optical illusion. Those feathers are actually brown, but appear blue because of something called structural colouration. This is the same phenomenon that creates iridescent colours, like those of a peacock. However, instead of only being visible from certain angles, the kingfisher's blue hues are non-iridescent, and so look the same from every direction. It's literally a trick of the light!

Aristotle famously thought that a mythical version of the kingfisher - the halcyon - built its nest on the surface of the sea. The reality is equally extraordinary: unlike many of our feathered friends, the kingfisher digs burrows into riverbanks. The tunnels are barely wider than the bird itself, but can be up to 90cm long. At the end sits a small chamber, angled slightly downwards so the eggs don't roll out.

After teaming up in February, breeding pairs will raise 2-3 clutches of 5-7 eggs through the spring and summer. Incubation lasts for around 20 days, and fledging for around 25 days. Once the chicks are ready to leave, their parents feed them for another 4-5 days before chasing them away - kingfishers are fiercely territorial, after all, and the next brood of chicks will soon be on its way.

The breeding season can be a great time to see the social behaviours of an otherwise solitary species. Early on, you might glimpse the male wooing the female by bringing her food; you can identify her by the reddish patch on her beak. Then, you might notice the pair clearing out an old nest tunnel or digging a new one. Later, you might spot them swapping places to go fishing or watch the chicks.

As its name suggests, the kingfisher is a formidable hunter. From its perch on a low-hanging branch, it patiently waits for its next meal to swim by; usually minnows and other small fish, but insects, tadpoles, and freshwater shrimp are also on the menu. Once its prey has been spotted, the kingfisher will bob its head to gauge the depth, and then dart down to take the plunge.

When it dives, the kingfisher closes its nictitating membranes - translucent third eyelids that protect its eyes while maintaining some vision. It spreads its wings, preparing to propel itself back to the surface. If its aim is true, it returns victorious to its streamside perch. Once there, it might stun its prey by hitting it against the branch; a necessary step for eating spiny fish like sticklebacks.

A key factor in the kingfisher's incredible hunting ability is its remarkable beak. The long, thin shape has a cross-section that resembles a diamond with curved edges. This means that when the kingfisher dives, water flows along the length instead of being pushed away, allowing for seamless entry. In fact, this shape is so effective that it inspired the design of the Japanese bullet train!

Sadly, our local kingfishers have to contend with a number of pressures. Disturbance by dogs or humans can scare them away from their nests, stopping them from feeding their young. Chemical and nutrient pollution can affect insect, amphibian, and fish numbers, reducing their food supply.

They can also be affected by severe winter weather. Freezing temperature can impact prey numbers, and even prevent fishing if the water ices over. Flooding can threaten their nests and make streams too fast for them to dive in. Some will have to migrate downstream, risking conflict with other kingfishers.

As such, the best way to support these beautiful birds is keeping their homes in a good condition. We're improving the health of seven local chalk streams through the Watercress and Winterbournes scheme, and pushing for their protection through the Save Our Chalk Streams campaign. If you can, please consider getting involved in these fantastic initiatives.

Watercress and Winterbournes

Save Our Chalk Streams