American Flamingo - Phoenicopterus ruber

Flamingos aren’t naturally pink! They get their coloration from beta carotene found in the blue-green algae they consume. The flamingos that consume blue-green algae directly are much pinker than flamingos that primarily consume the blue-green algae secondhand (via zooplankton/brine shrimp). 

Flamingos are also unique in their method of eating - their bills are designed to scoop the bottom sediment and then filter out the mud and silt, leaving only the blue-green algae or the brine shrimp in their mouth. They shake their head back and forth under the water after scooping up the sediment. The big, fleshy tongue of the flamingo pushes water back and forth in the mouth and facilitates the filtering of all that mud. They also swallow their food while their head is upside-down! The meaty tongue used to be considered a delicacy among the Roman elite.

Images:
Nature Neighbors: Embracing Birds, Plants, and Minerals. Nathanial Moore Banta for the American Audubon Association, 1914.

Osteologia Avium; or, A sketch of the osteology of birds. T.C. Eyton, 1867.

Northern or Single-Wattled Cassowary - Casuarius unappendiculatus

Cassowaries are one of the ratites - large, (generally) flightless birds. They inhabit the dense rainforests of Papua New Guinea, surrounding islands, and a small area of old-growth rainforest in Australia.

Unlike most birds, cassowary females are far more territorial than the males. Females will viciously attack any female who attempts to encroach into her territory, which can span several “satellite” male territories. During mating season, females will mate with one male, lay her eggs in his nest, and leave for the next male in her territory. In addition to the high energy output of laying the eggs (third-largest of all the birds), this polyandrous behavior allows the female to continue to control her territory while still passing on her genes.

The male both incubates the eggs and cares for the chicks when they hatch, and is much more aggressive than normal when the chicks are young, having even been seen keeping the females away from the nest area.

Cassowaries are one of the few birds that has killed humans outright - though attacks are uncommon, due to their rather secluded habitat, a boy named Philip McClean was killed in 1928, when a cassowary kicked him after he tripped and fell, severing his carotid artery. The bird had been chasing him because he and his brother had decided to try and kill it with clubs after finding it on their property, and probably wouldn’t have touched them if they hadn’t been beating it over the head.

Transactions of the Scientific Meetings of the Zoological Society of London. 1901.

Black-Necked Aracari - Pteroglossus aracari
Top, Bottom - 10-day-old juvenile
Center - Adult (male/female form similar)

Aracaris are toucans, in the genus Pteroglossus (along with the Saffron toucanet). Though the toucans are among the largest tropical birds, aracaris are relatively small members of their family. Aside from size, their omnivorous diet chiefly consisting of fruits, proportionally huge bill used for plundering fruits and nests of other birds, and their altricial (helpless at birth) chicks, are all characteristic of other toucans.

Top, Bottom: Tropical Wild Life in British Guyana. William Beebe, 1917.
Center: Os quadros de aves tropicais do Castelo de Hoflössnitz. Albert Eckhout, ca. 1653-1659.

aspidelaps:

biomedicalephemera:

The Juvenile Hoatzin (Opisthocomus hoazin)

It should first be noted that all birds are dinosaurs (order Saurischia, clade Theropoda), not just descendents of dinosaurs - modern genetic analysis strongly supports this cladistic organization. But given what we’re too often taught in schools, birds and dinosaurs are hard to reconcile in many peoples’ minds.

The juvenile hoatzin, however, makes it easy to see the reptilian traits that once dominated the early birds, and displays the unused genetic codes that lurk in the genome of modern avians. When they hatch, they’re equipped with lizard-like claws in front of their wings. Their use is described here, but in short, they use them to return to their nest and avoid predators. Their claws disappear by the time they leave the nest, having grown together into the metacarpals that support the wing structure.

Another fascinating trait of the hoatzins is their vegetarianism and their digestive tract. They have gut flora and fermentation similar to ruminants, which no other bird has. This is actually what leads to their being called “stink birds” - they exude a lot of stench with the fermentation process. The gut fermentation is so important to the hoatzin that the flight muscles attached to their keel are significantly reduced, to allow for more space for the stomach. They are weak flyers because of this. After a large meal, an adult hoatzin can spend up to two days doing almost nothing, allowing the leaves and greenery to have their nutrients released by their symbiotic gut flora.

Images:

Top: Attitudes of the juvenile hoatzin while climbing
Second row, left: Hoatzin nest with two eggs - Note proximity to water
Second row, right: Two hoatzin chicks preparing to dive, after appearance of threat from above
Third row, left: Hoatzin chick demonstrating strong swimming abilities
Third row, right: Hoatzin chick demonstrating poor locomotion on land
Bottom: Detail of hoatzin chick climbing, using neck, feet, and claws.

Tropical Wild Life in British Guinea, Vol 1. Curated by William Beebe, 1898.

It should be noted that the claws of Hoatzin are not actually simply because they are related to dinosaurs. Their claws actually re-evolved independently - they are not evolutionary leftovers at their core. While it could be considered a re-appearing gene because of their evolutionary history, it’s still something that would have to be selected over time and could have vanished again just as easily, not to mention it’s very unlikely (and impossible to prove) that it is the exact genome coming out of dormancy.

It’s more similar to dinosaurs when one thinks about convergent evolution than when one thinks about descendence, even if they are descendents too.

All of this is true, but I still like the hoatzin as an example of how to start to show people how birds really *are* dinosaurs - it’s a concept that many people don’t even begin to accept easily.

Hoatzin claws aren’t so much elongated talons-turned-wings like the Archaeopteryx seems to have, as they are a set of hooks on the front of a “chicken wing” structure. Note too, that Archaeopteryx and the hoatzin are not closely related at all (also the archaeopteryx may not even be a bird or bird relative/ancestor, but that’s a whole different matter).

Either way, the hoatzin (btw, if anyone’s wondering, that’s basically pronounced “Watsin”) is an interesting bird. The morphological changes in the wing bones as it matures are interesting enough, but the fact that it’s got such a weird digestive system are what really intrigue me.

It should be noted that while the hoatzin is a poor flyer, it’s not because it’s “primitive” or anything - it’s completely because they have a huge gut, and smaller flight muscles because of that. While their gut is a characteristic that some pretty ancient ancestors of theirs had (at least back to the Eocene), the species as a whole isn’t some evolutionary throwback, like some of the Crocodilians. The “hook-hands” of the hoatzin are relatively recent developments, as was noted. But their morphological similarities to the extinct Therapods still helps to remind people that dinosaurs and birds aren’t so different, after all.

The Juvenile Hoatzin (Opisthocomus hoazin)

It should first be noted that all birds are dinosaurs (order Saurischia, clade Theropoda), not just descendents of dinosaurs - modern genetic analysis strongly supports this cladistic organization. But given what we’re too often taught in schools, birds and dinosaurs are hard to reconcile in many peoples’ minds.

The juvenile hoatzin, however, makes it easy to see the reptilian traits that once dominated the early birds, and displays the unused genetic codes that lurk in the genome of modern avians. When they hatch, they’re equipped with lizard-like claws in front of their wings. Their use is described here, but in short, they use them to return to their nest and avoid predators. Their claws disappear by the time they leave the nest, having grown together into the metacarpals that support the wing structure.

Another fascinating trait of the hoatzins is their vegetarianism and their digestive tract. They have gut flora and fermentation similar to ruminants, which no other bird has. This is actually what leads to their being called “stink birds” - they exude a lot of stench with the fermentation process. The gut fermentation is so important to the hoatzin that the flight muscles attached to their keel are significantly reduced, to allow for more space for the stomach. They are weak flyers because of this. After a large meal, an adult hoatzin can spend up to two days doing almost nothing, allowing the leaves and greenery to have their nutrients released by their symbiotic gut flora.

Images:

Top: Attitudes of the juvenile hoatzin while climbing
Second row, left: Hoatzin nest with two eggs - Note proximity to water
Second row, right: Two hoatzin chicks preparing to dive, after appearance of threat from above
Third row, left: Hoatzin chick demonstrating strong swimming abilities
Third row, right: Hoatzin chick demonstrating poor locomotion on land
Bottom: Detail of hoatzin chick climbing, using neck, feet, and claws.

Tropical Wild Life in British Guinea, Vol 1. Curated by William Beebe, 1898.

sirjosephbanksfrs:

biomedicalephemera:

Apteryx owenii - The  Little Spotted Kiwi - In life and superficial lateral dissection

Though at first glance the kiwi appears to not have any wings, the lateral anatomical view with no feathers shows that external wings still exist. Of course, they are rudimentary at best, and useless for flying, but they still serve to balance the bird and are not considered vestigial. The only birds that had no wings were the giant Moas, also of New Zealand.

Transactions of the Zoological Society of London, Vol III. 1849.

Kiwis have minute wings, not considered to be vestigial because they serve the purpose of helping the animal to balance.

This is actually pretty true (that the tiny things DO have a function) in the Little Spotted Kiwi and the Brown Kiwi - you can see them being used like that in their natural habitat, which is generally rough terrain.

But I think a case could be made for them being truly vestigial in the Great Spotted kiwi. The size of the wings in the Great Spotted is smaller than even the wings of the Little Spotted, the weight is differently distributed in the two species (with a heavier hind-end in the Great), and the Great Spotted has proportionally larger leg muscles. Not to mention they also live in a flatter and less rough habitat, but I’m not sure how much that played into the differences in body structure.

That said, you’ll always have people arguing that even the most useless remnant of a limb or organ isn’t vestigial, because the body works around what it has - even if you watched the process of, say, horse leg evolution, and realized that eventually the remnants of the fibula probably won’t exist anymore, you can say that they’re not vestigial, because the muscles of the horse still partially attach to the fused parts of that bone.

Apteryx owenii - The  Little Spotted Kiwi - In life and superficial lateral dissection

Though at first glance the kiwi appears to not have any wings, the lateral anatomical view with no feathers shows that external wings still exist. Of course, they are rudimentary at best, and useless for flying, but they still serve to balance the bird and are not considered vestigial. The only birds that had no wings were the giant Moas, also of New Zealand.

Transactions of the Zoological Society of London, Vol III. 1849.

Artistic interpretations of sea life, birds, and reptiles

Between the beginning of the Scientific Revolution (which began in the mid-17th century) and the early-19th Century movement towards dry and clinical accuracy in both anatomical and zoological illustrations, there was a period of extravagance, showiness, and artistic expression in the sciences.

Instead of being solely geared towards other scientists, the artists sought to entice the general public and show off their vast collections, in many of their works. This can be seen in the medical illustrations of Frederick Ruysch, as well as here, in the zoological illustrations of Albertus Seba.

[h/t to Biodiversity Library’s blog for tipping me off to the interesting connections between two collections already in my archive]

Locupletissimi rerum naturalium thesauri accurata descripto, tome II & III. Albetus Seba, 1735.

Male Birds-of-Paradise, in repose (top) and on display (bottom)

Left to right: “Le Sifilet” [the Western or Arfak Parotia] - Parotia sefilata, Superb Bird-of-Paradise - Lophorina superba , “Le Nébuleux” [The Nebulous Bird-of-Paradise] - ??

Despite their incredibly different outward appearances, the Birds-of-Paradise are all very closely related. We know this because of their skeletal similarities, and, these days, their genetic similarities.

However, their close affiliation to one another genetically has also caused problems in pinning down the exact number of species in the family Paradisaeidae, as it turns out that within each of the fourteen genus, the species are able to (and occasionally naturally do) cross-breed with one another. This wild cross-breeding is believed to be the source of many of the specimens and illustrated birds that have never again, or very rarely, been seen in the wild.

An example of this cross-breeding is shown above, at right. The “Nebulous Bird-of-Paradise” is thought to either be a misrepresented Twelve-Wired Bird-of-Paradise (unlikely, given Jacques Barraband’s reputation as an ornithological illustrator), or a cross between two species living in nearby ranges of New Guinea. As the ranges of many different species and genus overlapped at the time of the specimens being gathered, it’s unknown which two would have created such a bird, or whether it would have been fertile (most wild cross-breeds of birds-of-paradise are). Genetic tests may give us the answers to these questions in the future.

Histoire naturelle des oiseaux de paradis et rolliers. Francois Levaillant, illustrated by Jacques Barraband, 1806.