Relatives of the dodo: Until it became extinct, almost no one believed it existed

The dodo from Mauritius was the first animal in the world to be confirmed extinct. There is even an English saying about it: "as dead as dodo". This large flightless bird was killed by humans and invasive animals brought by humans. It is unfortunate. However, the dodo has a relative who is even more unlucky.

The world's only remaining dodo soft tissue specimen | Ed Schipul / wikimedia

The solitary dove (Pezophaps solitaria), also known as the Rodrigues dodo, lives on Rodrigues Island, another island hundreds of kilometers west of Mauritius.

Like the dodo, it also became extinct due to predation by humans and invasive species. However, the dodo has become a classic case for promoting animal protection and a star of extinction, while the solitary dove has remained unknown in the eyes of the public and has even been given an unfortunate name of "destined to be lonely for life."

However, the solitary dove is actually a very strange bird, and the history of its discovery is so interesting that it is worth writing a story about it.

1

Beautiful, delicious, but unfortunate

We know about the solitary dove today thanks to a Frenchman named Francois Leguat. He and six companions were exiled to Rodrigues Island from 1691 to 1693. There, he made detailed observations and records of the solitary dove, and he also gave the solitary dove its name (solitaire).

Lugua's own drawing of a solitary dove, the only drawing of a living solitary dove | Hume, Julian P., and Lorna Steel. / Biological Journal of the Linnean Society (2013)

According to Lugua's notes, the solitary dove is a large bird that feeds on plants and cannot fly; it has a bullet-shaped bone tumor on its wings, which is its fighting weapon, and flapping its wings quickly will make a sound.

They are very solitary, but the couple cooperates closely. The lone dove only lays one egg at a time, and the couple incubates the egg together for 7 weeks, and then takes care of the chicks together for several months. During this period, they will not allow any of their kind to come within a radius of 200 yards (about 180 meters). Interestingly, the lone dove does not fight with the opposite sex. If a female lone dove comes to the male lone dove's territory, he will flap his wings to make a sound and call his wife to drive away the intruder; conversely, if a male lone dove comes, the female lone dove will also call her husband to fight.

Lugua's map of Rodrigues | wikimedia

Lugua also recorded some interesting and strange things: there was a stone in the gizzard of the solitary dove, which was as big as an egg. He doubted whether the throat of the solitary dove could swallow it. The female solitary dove was very beautiful, with some brown feathers and some light golden feathers similar to blonde hair. The most peculiar thing was that there were two protrusions at the base of the female solitary dove's neck, where the crop was located, and the feathers on them were white, like a fashionable girl. Lugua was probably afraid of offending morals here, so he said it vaguely, probably meaning that it was like a woman's breasts.

Lugua also did not miss the questions that everyone was most interested in: From May to September, the solitary pigeons grow very fat, and the male birds can grow to more than 20 kilograms. Their meat is delicious (by the way, the dodo is not delicious). The solitary pigeons walk in a grand manner and are not afraid of people at all, which makes it more convenient for greedy humans.

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Because of the internal circulation, the martial virtue is abundant

Lugua's notes were published in England in 1708. He was not the only person to have seen the solitary dove (a few others had also seen live solitary doves), but records of the bird were pitifully few at the time. Because his description was so bizarre, American scholar Geoffroy Atkinson even concluded that the solitary dove was made up, and that even Lugua was made up, and that the notes were just a fabricated novel, and that there was no such bird.

Picture of a solitary dove | Biodiversity Heritage Library

Just as people were willing to believe that the lone dove did not exist, the lone dove was quietly going to its end. The exact time is unclear, but the lone dove's extinction should have occurred in the 18th century. Someone lived on Rodrigues Island for 40 years since 1790 and never saw a live lone dove.

Surprisingly, since 1786, people have repeatedly discovered the bones of the solitary pigeon in the stalactite caves on the island. These bones were wrapped in minerals in the groundwater and preserved, and there are thousands of them in total. The bone tumor mentioned by Lugua was also found on the carpometacarpi (a bone unique to birds, as the name suggests, formed by the healing of the bones of the wrist and palm).

Carpal metacarpal bones of a solitary dove. Large tumors can exceed 3 cm in diameter | Hume, Julian P., and Lorna Steel. / Biological Journal of the Linnean Society (2013)

In 1789, nearly 100 years after Lugua recorded the solitary dove, this strange bird finally got its first scientific name, Didus solitarius, which is in the same genus as the dodo. Later, the solitary dove had its own genus. Today we know that the solitary dove is a relative of the dodo, and both belong to the pigeon family. Their ancestors were both able to fly, but they evolved into giant flightless birds on two isolated islands.

Although both the lone dove and the dodo are different in that they cannot fly, for example, the lone dove has a strong martial virtue.

Although the dove cannot fly, its wings are quite long, and its pectoral muscles are quite strong, so it can flap its wings powerfully; the bone tumors on the carpal bones are like two sledgehammers when wielded. Many traces of healing after fractures were found on the bones of the dodo, which is rare on the bones of the dodo, indicating that they often used this terrible weapon to fight each other (while writing this article, I found a boxer named Rodriguez from the Ultimate Fighting Championship. Coincidence, this must be a coincidence). Julien Tafforet, a sailor who also witnessed the live dove like Lugua, said that the sound of the dove flapping its wings was very loud, like thunder.

Skeleton of a solitary dove. The smaller one is female and the larger one is male. | Hume, Julian P., and Lorna Steel. / Biological Journal of the Linnean Society (2013)

By the way, the solitary pigeon is not unique in its martial virtues. The Victoria crowned pigeon (Goura victoria), a large ground-dwelling pigeon that still exists today, also uses its wings to hit its enemies. It also has bony protrusions on its wings, but they are very small.

There is a big difference between male and female lone pigeons. The female is only 60% of the male's size, which is a common feature in animals with extremely aggressive males. Why are lone pigeons so aggressive? It may be because there is not enough living space, so they have to compete with the most violent means. The rising sea level at the end of the Pleistocene reduced the area of ​​Rodrigues Island by 90%. It is really pitiful that they are crazy about involution for a place to live.

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Flesh and blood will always exist in the hometown

Other records of Lugua may also be scientifically confirmed. For example, stones in the gizzard have also been found in existing birds. Birds often swallow stones to help grind food. The stones swallowed by pigeons are quite large. The Nicobar pigeon (Caloenas nicobarica), a living relative of the solitary pigeon, weighs only one pound, but the stones in its gizzard are large enough to be used as handicrafts, which is why the Nicobar pigeon is illegally hunted.

For example, the rule that "a good man (woman) does not fight with a woman (man)" may not be because the pigeons have sportsmanship and implement a gender-separated competition system, but because the couples have their own ulterior motives. The flapping of wings may not be the pigeons calling for a mate, but their way of courtship. Whether it is Mr. or Mrs. Pigeon, when they find a strange fellow of the opposite sex, their first reaction is to have an intimate relationship with it; but their "original mate" will also come and drive away the competitor.

Computer reconstruction of a solitary dove based on its skeleton | Rodríguez-Pontes, Martín A. / Historical Biology (2016)

The most interesting thing is the bulge in the crop of the female solitary pigeon, which may really be a "breast"... The pigeon family has a strange feature - "milk production". The inner wall of the crop of the parent pigeon produces a special cell rich in protein and fat, which falls off and serves as nutritious food for the young pigeons, called crop milk. The two bulges that Lugua saw may be the solitary pigeon's abnormally developed crop, which is used to produce crop milk to feed the children.

But we have no way of knowing what the chicks of the dodo look like. A small number of live dodos and specimens have left Mauritius, but no dodos, alive or dead, have ever left Rodrigues. For some reason, the captured doves quickly starved to death, destined to perish in their own cramped homes.

Fighting doves with forest in the background | Hume, Julian P., and Lorna Steel. / Biological Journal of the Linnean Society (2013)

Rodrigues Island was once covered with forests and home to many unique creatures, but due to hundreds of years of human reclamation and logging, it has changed beyond all recognition. At least 20 bird species and two large tortoise species have become extinct, and 37 plant species are critically endangered. Most of the animals on Rodrigues Island disappeared silently, and in comparison, the solitary pigeon, which has preserved some records, seems to have a little luck.

References

[1] Hume, Julian P., and Lorna Steel. "Fight club: a unique weapon in the wing of the solitaire, Pezophaps solitaria (Aves: Columbidae), an extinct flightless bird from Rodrigues, Mascarene Islands." Biological Journal of the Linnean Society 110.1 (2013): 32-44.

[2] LISLEVAND, TERJE. "Possible resource-defence polygyny in the extinct Rodrigues Solitaire Pezophaps solitaria (Columbidae: Raphini)." Ibis 158 (2016): 199-201.

[3] Rodríguez-Pontes, Martín A. "Digital reconstruction of Rodrigues Solitaire (Pezophaps solitaria)(Aves: Columbidae) physical appearance based on early descriptive observation and other evidence." Historical Biology 28.3 (2016): 398-414.

[4] Storer, Robert W. "A possible connection between crop milk and the maximum size attainable by flightless pigeons." The Auk 122.3 (2005): 1003-1004.

Author: Little Wombat

Editor: pee pee shrimp

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