The island of Mauritius was once inhabited by large flightless dodo birds. They disappeared only four hundred years ago, but circumstances have developed in such a way that almost nothing is known about their life.
The dodo bird (Mauritian dodo, Raphus cucullatus) lived on the island of Mauritius for a very long time. The island itself is about 10 million years old, it arose as a result of volcanic activity and has never been part of a larger land mass. Once, after its formation, the ancestors of the dodo flew there, belonging to the family of pigeons, and so they remained there.
The island was not a bad place. There was a lot of food and there were no predators at all from which it would be necessary to flee in the air. The closest ancestors of the dodo gradually weaned themselves to fly - this ability on the island promised some troubles in the form of high energy costs, maintaining the "openwork" structure of the skeleton and the risk of being blown into the sea by the wind.
And then sailors appeared in Mauritius. First, the Arabs, but they somehow did not leave significant traces of their presence. The Europeans came a little later. These began to cut down forests, and most importantly, they brought rats, pigs and even crab-eating macaques to the island. The Dodos could not stand the combined offensive of civilization and died out at the end of the 17th century.
Everything we know about this bird now comes from either bone remains or evidence from Dutch and, less often, English sailors who visited Mauritius in the 17th century. There are few written sources, and they are laconic - none of their authors expected that their descendants would study their letters for this purpose.
One of the incomprehensible features of the sources is the difference in the description of the appearance of dodos by different authors. As if they saw different birds, which had normal feathers, then down, then one and the other mixed.
A team of biologists from South Africa decided to solve this and other mysteries. Strictly speaking, their work was devoted to the entire life cycle of the dodo, but we will still keep feathers in mind as the most outwardly noticeable factor.
The team, led by Dolphin Angst of the University of Cape Town, found that the dodo's life cycle has evolved in line with the seasonal weather cycles in Mauritius. The bird's job was to cope with harsh weather and food shortages between November and March.
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"Bird Landscape" by Rolant Severi, 1628. Dodo is visible in the lower right corner
Having gone through hard times, the birds molted, shedding their old plumage. By July, they had fresh feathers, and in August a new breeding season began. Apparently, reports of dodos, dressed in down, related precisely to the period of molting. It should be noted that it is easier for a flightless bird, and even in a warm climate, to molt - this can be done without haste.
For the analysis, 22 bones from different individuals were used. With one exception, these were leg bones. In Mauritius, they are generally found more often than anyone else. Dodo remains are usually confined to swamps, in which the lower part of the body has the best chance of burial - the upper part is taken away by scavengers.
Some of the birds, judging by their bones, were young: their bones bear traces of rapid growth. Other bones had large molting cavities. In the opinion of the authors of the work, the fact of their formation indicates an increased consumption of calcium during the growth of new feathers. Calcium was taken from bone tissue.
Two bones belonged to females. They contain a specialized tissue - medullary bone, which is a source of calcium during the formation of the shell.
The very fact of seasonal molting in birds is not a discovery, but no one has ever noted it in the dodo, which became extinct even before the advent of ornithology as a science. Of interest is not so much the molting itself as the ability of modern science to establish its fact.
Sergey Sysoev
