Featured Creature: Kingfisher

What creature often looks blue, but isn’t, is found on every continent but Antarctica, and inspired a train’s design?

Kingfishers! (Alcedinidae)

Kingfishers are kind of like snowflakes. They both float and fly through the air, and no two are really alike. It’s what I love so much about them. Each kingfisher presents characteristics unique to their own lifestyle. They make me think of people. Like kingfishers, we live almost everywhere on Earth and we’ve all adapted a little differently to our diverse environments. I hope as you get to know the kingfisher, you’ll start to feel a small connection to these birds as I have.

Kingfishers are bright, colorful birds with small bodies, large heads, and long bills. They’re highly adaptable to different climates and environmental conditions, making them present in a variety of habitats worldwide. Many call wetland environments like rivers, lakes, marshes, and mangroves home. Now, their name might lead you to think all kingfishers live near these bodies of water, but more than half the world’s species are found in forests, near only calm ponds or small streams. Others live high in mountains, in open woodlands, on tropical coral atolls, or have adapted to human-modified habitats like parks, gardens, and agricultural areas.

Even so, you’re most likely to spot them in the tropical regions of Africa, Asia, and Oceania, but they can also be found in more temperate regions in Europe and the Americas. Some species have large populations and massive geographic ranges, like the Common Kingfisher (Alcedo atthis), pictured above, which resides from Ireland across Europe, North Africa and Asia, as far as the Solomon Islands in the Pacific. Other kingfishers (typically insular species that evolved on islands) have smaller ranges, like the Indigo-banded Kingfisher (Ceyx cyanopectus), which is only found in the Philippines.

Birds of a Feather

Kingfishers are small to medium sized birds averaging about 16-17 cm (a little over 6 inches) in length. They have compact bodies with short necks and legs, stubby tails and small feet, especially in comparison to their large heads and long, pointed bills. While many species are proportioned the same way, some are quite distinct. Paradise Kingfishers (Tanysiptera), which are found in the Maluku Islands and New Guinea like the one pictured below, are known for their long tail streamers. The African Dwarf Kingfisher (Ispidina lecontei) is the world’s smallest kingfisher at just 10 cm (barely 4 inches) long, and is found in Central and West Africa. The largest is the Laughing Kookaburra (Dacelo novaeguineae), coming in at a whopping 41-46 cm (15-18 inches) long, and is native to Australia.

Now, I know what you’re thinking: ‘Wait, are kookaburras and kingfishers the same thing? Sometime. Out of all 118 species, only four go by the name kookaburra: the Laughing Kookaburra (Dacelo novaeguineae), the Blue-winged Kookaburra (Dacelo leachii), the Spangled Kookaburra (Dacelo tyro), and the Rufous-bellied Kookaburra (Dacelo gaudichaud). Native to Australia and New Guinea, the kookaburra are named for their loud and distinctive call that sounds like laughter. Sometimes their cackles can even be mistaken for monkeys!

So,  are they as colorful as everyone says?

Yes! If you ask anyone who has seen a kingfisher to describe what it looks like, they will most likely go on and on about its color. Kingfishers are bright and vividly colored in green, blue, red, orange, and white feathers, and depending on the species, can be marked by a single, bold stripe of color. These features all accent the bird’s most recognizable feature, which is the blue plumage on their wings, back, and head. But here’s where things get interesting: Kingfishers don’t actually have any blue pigment in their feathers.

So, what gives? It’s something called the Tyndall effect. What’s happening is that tiny, microscopic keratin deposits on the birds’ feathers (yes, the same keratin that’s in your hair and nails) scatter light in such a way that short wavelengths of light, like (you guessed it) blue, bounce off the surface while all others are absorbed into the feather.

It sounds a little strange, but you see it every day. It’s why we see the sky as blue, too.

Are kingfishers Really Kings of Fishing?

Yes! And no. Kingfisher species are split into three subfamilies based on their feeding habits and habitats: the Tree Kingfishers (Halcyoninae), the River Kingfishers (Alcedininae), and the Water Kingfishers (Cerylinae). Despite their name, many of these birds primarily prefer insects, taking their prey from the air, the foliage, and the ground. They also eat reptiles (like skinks and snakes), amphibians, mollusks, non-insect arthropods (like crabs, spiders, scorpions, centipedes, and millipedes), and even small mammals like mice.

Tree Kingfishers reside in forests and open woodlands, hunting on the ground for small vertebrates and invertebrates. River Kingfishers are more often found eating fish and insects in forest and freshwater habitats. Water Kingfishers, the birds found near lakes, marshes, and other still bodies of water, are the fishing pros, specialize in catching and eating fish, and are actually the smallest subfamily of kingfishers, with only nine species.

Because the diets of kingfishers vary, so does the size and shape of their bills. Even though all species have long, dagger-like bills for the purpose of catching and holding prey, those of fishing species are longer and more compressed while ground feeders have shorter and broader bills that help them dig to find prey. The Shovel-billed Kookaburra (Clytoceyx rex) has the most atypical bill because it uses it to plow through the earth looking for lizards, grubs, snails, and earthworms. 

Can the blue-but-not-really-blue kingfisher get any more interesting? 

Oh yes, yes it can. Ready for another physics lesson? Kingfishers have excellent binocular vision, which means they’re able to see with both eyes simultaneously to create a single three-dimensional image, like humans. Not only that, but they can see in color too! But what makes them so adept at catching fish is their capability to compensate for the refraction of light off water.

When light travels from one material into another (in this case, air into water), that light will refract, or bend, because the densities of air and water are different. This makes objects look as though they are slightly displaced when viewed through the water surface. Kingfishers are not only able to compensate for that optical illusion while hunting, but they also can accurately judge the depth of their prey as well. 

But, triangulating underwater prey is only half the battle. Then you’ve got to catch it.

Fishing species of kingfishers dive no more than 25 cm (10 inches) into the water, anticipating the movements of their prey up until impact. Again, what happens next differs depending on which kingfisher we’re talking about. Many have translucent nictitating membranes that slide across their eyes just before impact to protect them while maintaining limited vision. Others, like the Pied Kingfisher (Ceryle rudis leucomelanurus), actually have a more robust bony plate that slides out across its eye when it hits the water—giving greater protection while sacrificing vision.

Kingfishers usually hunt from an exposed vantage point, diving rapidly into the water to snatch prey and return to their perch. If the prey is large (or still alive), kingfishers will kill it by beating it against the perch, dislodging and breaking protective spines and bones and removing legs and wings of insects. The Ruddy Kingfisher (Halcyon coromanda) native to south and southeast Asia, removes land snails from their shells by smashing them against stones on the forest floor.

Learning from kingfishers

Occupying a place fairly high in their environments’ pecking orders (trophic level) makes kingfishers susceptible to effects of bioaccumulation, or the increasing concentration of pollutants found in living things as you climb the food chain. This phenomenon, coupled with the kingfisher’s sensitivity to toxins, makes the bird a fairly reliable environmental indicator of ecosystem health. If a kingfisher population is strong, that can indicate their habitat is healthy because the small aquatic animals they feed on aren’t intaking poisons or pollutants. When problems are detected in a kingfisher population, it can serve as an early warning system that something more systemic is wrong.

But that’s not the only thing we can, or have learned, from kingfishers. In 1989, Japan was looking for a way to redesign its Shinkansen Bullet Train to make it both faster and quieter. As the train flew through tunnels at 275 km/h, massive amounts of pressure would build up, reigned in by the front of the train and the tunnels’ walls. Upon exiting the tunnels, that pressure would release, sending roaring booms through the homes of those living nearby. Engineer Eiji Nakatsu was not only the project’s lead, but birdwatcher as well. Noting the kingfisher’s ability to plunge into dense water at incredible speeds with hardly a splash, Nakatsu and his team remodeled the front of the train with the bird’s beak in mind. The result not only solved the problem of the boom, but also allowed the train to travel faster while using less energy.

Kingfishers: A Little More Like You Than You Think

In learning  about the kingfisher, I saw a little bit of us. We all come from the same family, even if we each do things a little differently.  I think for me, this gets to the root of why finding our connections with all living things matters, not just because they give us inspiration to solve human problems or because we depend on them to keep natural systems in balance, but because this is just as much their Earth as ours. 

Let’s do our part,

Abigail

Sources and Further Reading:

• Animalia
• Animal Diversity – Alcedinidae
• Songbird Survival – Kingfisher
• Long-term anthropogenic stressors cause declines in kingfisher assemblages in wetlands in southwestern India, C.T. Shifa, et. al, 2023
• Britannica – Kingfisher
• Nat Geo: Overheard