You can encounter it in a snowy landscape in Hokkaido (Japan), where it can be seen all year round. But given the latitude where we live, you probably first saw the Shima-enaga on the Internet as we now know it: the little bird that looks like a snowball rivals the red panda in adorableness and has such traction that it attracts tourists from all over the country just to see it and has its own business system. But behind this bird’s cuteness lies a true ornithological rarity: cooperative breeding.
presentation. The shima-enaga is a subspecies of the common mythic or long-tailed tit (Aegithalos caudatus) that lives on the island of Hokkaido. It is one of the smallest birds in Japan, weighing only 9 grams and measuring 12 – 14 cm, half of which is the tail. It’s literally all feathers.
It differs from the rest of Japan’s chickadees in that it has a black stripe over the eye as an eyebrow, whereas the Shima-enaga has a completely white head. And well, it’s known as the Snow Fairy for obvious reasons.
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Why did this happen?. The ball shape has a physiological explanation: birds escape the cold by fluffing their plumage, which creates a layer of air and insulates the feathers. And it doesn’t have much room: due to its small size, the long-tailed tit is very sensitive to bad weather.
In addition, they crowd together: outside the breeding season, these birds sleep in rows where they compete to avoid extremes for value: according to a study (conducted with species groups in captivity, not Shima-Enaga) they lose an average of 9% of their body mass in one night, and those at the extremes lose more than those in the center.
Longevity family upbringing. The most interesting thing about this bird, and not only the Shima-enaga but also the long-tailed tit, is that it breeds jointly with helpers. More specifically, those who redirect their care are usually males who fail to reproduce on their own and who help related males breed.
Of course, they don’t do this with just anyone: an experiment showed that potential helpers don’t help if they don’t have close relatives, and while they can choose nests of relatives and non-relatives, almost all of them help relatives. How do they know them? by voice. And what’s more, they learn it: they recognize their relatives by the distinctive characteristics of their familiar calls, which they learn from the adults who feed them when they are young. This cooperation does not end during the breeding season: beyond, long-tailed jays prefer to associate with relatives in winter flocks.
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cover Alan Aprilio pen_ash
