Written By: Sarah Girton
One of the things I love most about birds is how specialized each species is. Even closely related birds like Darwin’s finches (who only split off from each other an estimated 2-3 million years BP), have specialized beaks for their preferred food sources that range from island to island. This week we are going to look at species that are incredibly specialized, both physically, and behaviorally.
- Hoatzin
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It’s a bird! It’s a plane! No, it’s…oh, wait, that IS a bird! It’s the Hoatzin, and they are definitely worthy of being on this list. Native to the forests of the Amazon, these birds split off from other birds about 64 million years ago.
The chicks of this species possess a claw on each wing that they use to climb around the trees – which they can do shortly after birth. Let the legendary David Attenborough show you just what I’m talking about…
Another unique thing about these birds is their extremely specialized digestive system. For one thing, its crop is so large that it has forced the flight muscles in their chest to shrink, resulting in poor flight capabilities. Food can take up to 45 hours to pass through the Hoatzin’s digestive system. Additionally, the leaves they prefer to eat have a very pungent smell, causing the locals to give it the nickname “stinkbird”.
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2. Shoebill Stork
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Shoebills can be found around wetlands in East Africa. This large member of the stork family possesses a rather unique bill, thus the name. Reminiscent of a Dutch wooden clog, these large bills are perfect for eating some of the larger prey that the birds hunt. Anything from snails and rodents all the way up to Nile monitors, catfish, and snakes are on the menu for these guys.
Something else those huge bills are good for is bill-clattering, which oddly enough sounds similar to machine gun fire! Listen below:
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3. Sword-billed Hummingbird
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Our next bird is almost as small as birds can get. This is also a bird with an extremely unique and specialized bill; in fact it is the only bird with a beak longer than its body! This allows the bird to access food sources that other hummingbirds cannot.
Some flowers even co-evolved with the sword-billed hummingbird, like the passionflower Passiflora Mixta, whose long, tubular shape is only accessible by this bird. It’s a symbiotic relationship; the flower has a guaranteed pollinator, and the sword-billed hummingbird has a guaranteed food source all its own. You are likely to see this bird in the Andes, as they prefer a mountainous subtropical environment.
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4. Kiwi
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Kiwi are a small family of birds endemic to New Zealand. Like many island dwelling-creatures, they have become hyper-specialized to their environment. They have no wings, and in fact their arms are so small that they aren’t even visible without a detailed inspection of the skeleton.
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These little birds also lay the largest eggs in proportion to their body of any other bird. That egg ends up being about 20% of the pregnant bird’s weight. The loss of flight is most likely the reason for this, as the birds are strictly ground-dwelling, so the extra weight is not a problem for them.
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- Kākāpō
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Another New Zealand native, the Kākāpō is also flightless. Birds like these who evolve on islands often lose the ability to fly because of the lack of natural predators. Once humans arrived, that all changed, and now we have to try extra hard to help these birds recover from past actions.
Outside of owls, nightjars, and the like, there are not many nocturnal birds in the world. The Kākāpō is one of the few exceptions.
The mating call of the Kākāpō is just as unique as the bird itself. A deep, booming noise emanates from the male’s throat…and it’s so deep that it can be difficult for some people to hear.
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- Cassowary
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Here is a very handsome bird with some equally unique features. Instead of brightly colored feathers, the Cassowary’s head is a stunning array of blues and reds. The species pictured here is the southern cassowary. Cassowaries are some of the largest living bird species, right behind the Ostrich and Emu.
Another unique feature of this bird is their casque — the large bony structure on top of the head. This feature allows the bird to get rid of excess heat, which I imagine comes in handy since they live in Australia and New Guinea!
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7. Butcherbird
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If you haven’t noticed by now, Oceania has a LOT of unique bird species, and the Butcherbird is among them! So what’s so unique about this bird? Turns out they have rightfully earned their name, as these birds are known for the way they store food. By impaling their prey (usually large insects, lizards, and other small creatures) on a branch, the birds have an easier time eating. They also store their food this way. It my seem macabre but it’s actually a pretty smart and efficient way to eat and store food.
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8. Picathartes
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Like the Hoatzin, this is a bird species that split off from the rest of the avian kingdom very long ago — about 44 million years ago to be exact! The White-necked Rockfowl pictured above is one of two confirmed species in the genus Picathartes, the other being the Grey-necked Rockfowl. Both are native to west Africa.
One of their most interesting features is that head. To me it looks like they are wearing a rugby helmet! Aside from their very unique appearance, these birds have some unique behaviors for jungle dwellers. They build mud nests on the underside of rocky outcroppings, to protect themselves from the rain.. Their young also take a lot longer to hatch and fledge than many other birds their size or smaller. Incubation takes almost a month, with another month before the babies are ready to leave the nest. There is also rampant infanticide by members of the same species, something else rare among birds.
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9. Great Potoo
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Just look at those big ol’ eyes and that huge mouth! This bird has evolved some seriously amusing characteristics. Found throughout Central and South America, they are nicknamed the “Ghost Bird”… probably a reference to their haunting call, which can be heard in the video below.
During the day, the Potoo will stand tall upon a tree stump or branch (stretching out into a pose that looks vaguely snooty!), keeping their eyes closed to further blend in with their environment. But they can still see you! There is a small slit in each eyelid that allows them to still keep an eye out for predators.
Which of these incredible birds stuck out to you the most? Are there any bird species I didn’t mention that you find particularly unique or interesting? I would definitely be open to another installment of this post in the future so I would love to hear your ideas!
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