Chubby Bird: I'm not fat, I just have big breasts

My favorite animal literature writer, Vi Bianchi, wrote about a kind of "bird that loves to take cold water baths" in his masterpiece "Forest News". He described it like this:

That morning, it was so cold that one's nose could freeze off. Although the sun was shining brightly in the sky, our forest correspondent had to scoop up snow several times to rub his frozen white nose.

So he was very surprised to hear the black-bellied bird singing happily on the ice.

When he walked over to take a look, the bird jumped high and then dived into the ice hole.

Watch me jump into the river! | Rolf Nylinder / youtube

"It's fallen into the river! It's going to drown!" thought the forest correspondent, and he hurried to the ice hole to rescue the crazy bird.

But the bird was paddling in the water with its wings, just like a swimmer paddling with his arms.

The black back of the bird flickered in the clear water, like a little silver fish.

The fat boy who loves diving

With just a few strokes, he pointed out the peculiarity of this little bird and clearly described its underwater behavior. The master is truly extraordinary.

What kind of bird is this that the forest correspondent thought was "mad and jumped into the river"? It is called the river bird Cinclus cinclus, a bird that has a very close relationship with water.

The reason why the river crow "jumps into the river" is not because it likes winter swimming, but because it needs to go to the bottom of the water to find food. In general, passerine birds usually do not stay near the water except for drinking water and bathing. Only the wagtail, red-tailed water robin, white-capped brook robin and other birds often move around the water, but they are limited to the waterside. However, as a member of the passerine order, the river crow not only lives by the water all year round, but also gets most of its food from the water. It can be said to be an "outlier" among the passerines.

A cute little river cuckoo with a rounded shape | Grzegorz Chrupała / Wikimedia Commons

Although the river cuckoo is widely distributed, there are not many species, with only 5 species in the world. The American river cuckoo lives in North America, the white-capped river cuckoo and the rare brown-throated river cuckoo can be found in South America, and the brown river cuckoo occupies a vast area in South Asia and East Asia. The river cuckoo (or white-breasted river cuckoo) is mainly based in Europe, but it has also expanded its distribution range to northwest Africa, West Asia, Central Asia and western my country (the eastern part is the territory of the brown river cuckoo).

"Flying" underwater

The river crow lives by fast-flowing streams. It likes to stand on rocks in the water, often squatting, with funny movements. The river crow mainly preys on aquatic insects such as mayflies, stoneflies, and caddisflies in the stream, and occasionally eats small fish, shrimps, or tadpoles. These little guys are plump but have smooth body lines, short wings and tails, and except for the white throat and chest, the rest of the body is dark brown. This body shape and color scheme reminds people of puffins that dive to fish in the northern waters. The two do have an important thing in common: river crows, like puffins and penguins, use their wings to paddle underwater, while most diving birds such as loons, grebes, cormorants, diving ducks, and mergansers use flippers to paddle when diving. From another perspective, the river crow is also "flying" underwater.

American river owl C. mexicanus sneaks underwater | National Geographic / youtube

The chubby appearance of the river blackbird is actually an outward manifestation of its adaptation to a diving life: in order to prevent water and heat insulation, the river blackbird's feathers are very thick and dense; in order to be able to "fly" underwater against the current, the river blackbird's pectoral muscles are very developed; in order to protect its eyes underwater, the river blackbird has a developed nictitating membrane (third eyelid); in order to avoid choking on water, the river blackbird's nostrils have valves that can be closed when diving; in order to be able to hold on to the slippery stones in the stream, the river blackbird's feet are strong and powerful.

The river crow is small, usually only 15-20 cm long and weighs only 55-75 grams. Once its feathers are soaked, it is easy to suffer from hypothermia and freeze to death. In order to ensure that its feathers are watertight, the river crow's uropygial gland is 10 times larger than that of other passerine birds. Whenever it has time, it will smear the oil secreted by the uropygial gland on its feathers to achieve the effect of "getting out of the water without getting wet". When the river crow dives into the water, a layer of air film will remain around its body, making this dark-colored bird appear silvery in the water.

A ball of butter standing on a stone | Alpo Roikola / Wikimedia Commons

With the multiple protection of thick feathers, waterproof grease and air film, the river gull has not only become a master diver who can stay underwater for 15 seconds, but also one of the least cold-resistant birds: as long as the stream is not completely frozen and the river gull can go into the water to find food, they can survive in the severe winter with the lowest temperature reaching minus 45 degrees Celsius.

The spirit of the stream

Because they are not afraid of cold, river crows start courting in early spring. Male river crows choose to build nests under tree roots, on cliffs, in cracks in rocks, under bridges, or even behind waterfalls. The nest site should be neither too far nor too close to the water. If it is too far, it will be inconvenient to find food, and if it is too close, it will be vulnerable to floods. This is a test of the wisdom and experience of male river crows. Once the pairing is successful, the female river crow will help her husband to arrange the nest and maintain the territory. Female river crows usually lay 4-5 eggs per nest, and the incubation period is 16 days. The young birds can leave the nest after being fed by their parents for one month. After leaving the nest, the young birds will start to live independently after 10-15 days of learning and training.

American river blackbird chicks begging for food from adults | National Geographic / youtube

If the first nest of chicks leaves the nest early and there is more food, the couple will lay another nest of eggs in the original nest and give birth to the second nest of chicks. At this time, the female is busy incubating the eggs, and the male is responsible for feeding and teaching the chicks who have just left the nest. Interestingly, the fledglings of the river crow will jump out of the nest to escape when disturbed. At this time, they cannot fly, but they can swim and dive. The chicks that escape the nest will dive into the water to hide.

The river slug has long been chosen as a symbol of clean water. It lives only in streams and rivers with clean water and fast currents. Pollutants kill the aquatic insects they feed on, and algae blooms in still water block their vision for food on the bottom, making it impossible for them to survive. In a study conducted in Italy, it was found that 93.3% of unpolluted rivers had river slugs, while 93.7% of polluted rivers had no river slugs.

Standing on flowing water | Erikottodamm / Wikimedia Commons

At the same time, another threat is also destroying their homes: dams and hydroelectric power stations. In particular, some diversion hydroelectric power stations will use culverts or pipes to concentrate the water flow of natural rivers in mountainous areas for power generation, which will cause the water flow of mountain streams to decrease or even dry up, greatly affecting the stream ecosystem.

Although river turtles are widely distributed and numerous globally, and their survival is not a problem, it would still be a great pity if the clear mountain streams no longer flow, the gurgling of water can no longer be heard in the silent forests, and the little figures of river turtles no longer crouch on the once wet rocks.

References

[1] Encyclopedia of Birds, Christopher Perris;

[2] Man and Nature magazine, Issue 6, 2007, p60: “Diving River Crow, Waterfall Spirit”;

[3] Forest Newspaper Winter, [former Soviet Union] Vitali Valentinovich Bianchi;

[4] ADW: Cinclus cinclus: INFORMATION

[5] Amaze-wing Facts About The Dipper Bird For Kids

[6] Aqueduct hydropower station - Baidu Encyclopedia

[7] White-throated dipper (Cinclus cinclus) - JungleDragon

[8] Zheng Guangmei, “Distribution and Classification List of Birds of the World”

[9] A Field Guide to the Birds of China, by John MacArthur and Karen Phillips, translated by Finch Ho.

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