A large colony of thrushes settles in the forest belt every year. They live there white-browed thrushes (Turdus iliacus) and blackbirds (Turdus pilaris). In summer and autumn, they will make devastating raids on the surrounding gardens, and now they are building nests, laying eggs and hatching chicks. These are rather noisy and scandalous birds: they try to drive away any potential enemy that has entered their territory with the whole flock: with a loud scream, flapping of wings, and if all these methods do not help, then with targeted shelling with droppings. You can often see how they drive away the crows in this way. Any person walking along the path also causes a loud panic. But I still reasonable man, and such behavior of birds, on the contrary, unmasks their nests. It seems like I’m just walking along the trees, in one place the screams increase sharply, I look around - but here it is a nest! As if he wasn’t specifically looking for it, they slipped it on themselves. Fieldfare nests are high, in the forks of trees, on thick branches, twisted from blades of grass and fastened with mud from above, while redwings build nests low, not more than a meter, on old stumps or half-fallen branches, or even on the ground. I pass by, one of the parents flies up from the nest, swears like a thrush from nearby branches, and I can’t help curiosity, I look into the nest for a second. Here they lie, 5 neat testicles, slightly smaller than quail ones. And not " blue as thrush eggs', as the song says. The color of the eggs is greenish-bluish, with grayish-brown speckles. And a week later, in the same nests, there are just hatched chicks, still pink, naked, with huge closed eyes. And only along their backs, like some small dinosaurs, they have a mane of a white fluff. So far, they just sometimes change their position and yawn, but soon they will begin to actively open their beak and squeak, demanding food from their parents.

On the picture white-browed thrush (Turdus iliacus). The smallest and one of the most common representatives of the thrush family in the territory of the former USSR. Length 22 cm, weight rarely exceeds 60 g. The color is brownish-green (olive-brown) on the back and light with dark (olive-brown) specks below. Breast-flanks and underwing coverts are rusty-red. Above the eyes is a whitish-yellow eyebrow; hence the Russian name for this bird. The female looks paler than the male.

Whitebrow is a bird that is not afraid of the cold. This species of thrush arrives early and departs late from the nesting site. In total, the redwing stays in these places for about six months. The beginning of the arrival of birds also depends on weather conditions and can vary from one to three weeks. As a rule, mass arrivals to nesting sites begin in April and end in early May.

In city parks, the redwing settles more crowded, and in natural forests, where there is much more space, it is dispersed. This bird prefers birch undergrowth, in which there is a small admixture of spruce growth. Whitebrow prefers light places where there are many bushes and water bodies, and avoids dark spruce or pine forests.

The food of the redwings consists mainly of insects, earthworms, various butterflies and caterpillars. Earthworms, during the period of feeding the chicks, are brought in their beaks not one at a time, but in a whole bunch, which descends into the nest, and then is already distributed among the chicks.

Thrush fieldfare (Turdus pilaris) is also a common species of thrush. The body length is 22–27 cm. The plumage of the back is dark brown, the abdomen and underwings are white, the wings and tail are blackish-brown. The chest and sides are buffy with dark streaks. Restless and very active bird, constantly making characteristic sounds chak ... chak ... chak, in an alarming state, a deafening rattle of ra-ra-ra begins

Fieldfare differs from other thrushes primarily in its way of life. Although some pairs nest in isolation, most of them gather in medium-sized colonies of 30-40 pairs. They like to settle in park plantings and in copses, along the edges of forests, closer to wet meadows. Fieldfare is not found in dense forests. Fieldfare eats both animal and plant foods. In winter, flocks of fieldfare flock to feast on ripe mountain ash and other berries (for example, sea buckthorn).

Fieldfare nests in colonies (up to 30 pairs). Nests are strong and deep bowls, which are either high or low, or completely open, or disguised. Some colonies are completely ruined by crows, jays and magpies. Thrushes defend themselves by throwing stones down at their enemies and dousing them with droppings. Dung bombs are dangerous weapons, as they can contaminate and glue the plumage of enemies to such an extent that they cannot fly. People expect the same "shelling" if they come to the colony.

The nest in this species of birds is built by the female. The task of the male is to accompany and protect the nesting site and his soulmate. The female, if possible, collects material for construction nearby. The nest is cup-shaped, rather massive, lined with soft grass from the inside.

Redwings start building nests at the end of April, about a week after the start of construction, the first egg is laid. If a bird settles in a ready nest, then egg-laying is accelerated. During the choice of a nest or its construction, the bird becomes very careful, it does everything to make the nest invisible. It is common for redwings to nest close to the ground. If only there is reliable camouflage and support, birds are happy to nest there. They love the bases of various trees, or use small half-decayed stumps.

It is extremely rare to see a redwing nest located on a hill, in hollows of trees, or on fences and fences. But, if the white-brows have a choice - to nest on a hill, or simply on the ground overgrown with grass, then the second option for these birds will be preferable. The only exception are parks, which are often visited by people. In this case, redwings make nests in trees, out of reach of park visitors.

The shape of the nest in whitebrows can vary depending on the nesting site. If the base is strong, then the nest will be more massive and larger. And if the nest is built on thin branches of a bush, then it will be light and elegant. You can see a randomly made nest if it is located on the ground, and a primitive nest in the form of a hole, located in the depths of a rotten stump.

The clutch contains 4 to 7 eggs. The eggs are greenish with brown spots. Incubation begins after the laying of the last egg and lasts 12 days. During the summer, laying occurs twice.

Let's look at the color of thrush eggs, are they really blue, and why did nature choose such an impractical and rather noticeable color for them? In the color catalog there is a completely official name "color of thrush eggs" (robin egg blue) for the color with the code # 00CCCC, it's like this:

I found an interesting article on the Popular Mechanics website: Why do thrushes have blue eggs?

It would seem that the bright, predator-attracting color of the eggs is a dubious evolutionary advantage; much more likely to survive in chicks that hatch from speckled or plain eggs mimicking the environment.

However, the bright fashionable eggs of some songbirds, including the thrush, are an indisputable fact, and scientists have been trying to explain it for a long time. Obviously, the blue color of the eggs should be an advantage that outweighs the increased risk of a snake, marten or hedgehog finding the clutch. The most common theory among ornithologists today is that the blue pigment in the shell serves the thrushes as protection from the sun.

Some songbirds lay eggs of different colors and shades - from white to bright azure. It was this that made it possible to determine exactly how the shell of eggs of the same species, but of different colors, conducts sunlight. It turned out that the blue pigment reflects ultraviolet radiation that is harmful to DNA; however, at the same time, the blue shell absorbs that part of the infrared rays that warms up the contents of the egg, accelerating embryonic development, which leads to a number of other problems.

The conclusion is that the blue coloration of the nest eggs is the result of a delicate balance between the desire to protect against UV rays and not to overheat the egg; this strategy only works in certain climates, and even then not in every case - so some birds lay eggs of different colors.

In the same nests as in the previous photos, after some time, chicks hatched: pink, wrinkled, with a sloppy tuft of fluff on the head and along the spine. A sort of microscopic pterodactyls.

They are very small, with huge black eyes that have not yet opened in relation to the size of their heads.

They will not be in the nest for long: the chicks will quickly grow up, jump out of the nest, and will already be hiding in the grass, where their parents will bring them food.

After the chicks leave the nest, and this happens 10-12 days after birth, they live right on the ground. Even without being able to fly, they are very mobile and move quite long distances from their homes. However, they do not lose each other, as they constantly hear the voice of other chicks, and parents direct the actions of their children, showing where to move.

As soon as the chick masters the ability to fly, its mobility increases even more, but they take off only if they are in danger.

And a short video with white-browed thrush chicks in the nest, where there are a few more unhatched eggs:

Traveler Thrush Nest (Turdus migratorius). The bird lives in northern and central parts of North America.

Gwen's River City Images / flickr.com

The color of the eggs of bird species living in cold climates is determined by thermoregulation, reported in Nature Ecology&Evolution. In a cold and cloudy climate, birds lay darker eggs, and in southern latitudes, pigmentation, apparently, already depends on several factors - the color and brightness of eggs in the inhabitants of the tropics and subtropics changes much more often.

Bird eggs come in different colors, plain or covered with spots and dots. The white color is determined by calcium carbonate, the pigment biliverdin gives them different shades of green-blue color, and protoporphyrins are responsible for the brown or reddish color. But what determines the color of the eggs is still not completely clear, although ornithologists have assumptions about this. On the one hand, pigmentation may play a role in thermoregulation. Dark-colored eggs absorb more solar energy that accidentally enters the nest, and they are more likely to overheat. Therefore, it is likely that dark-colored eggs should be more common in northern latitudes, where there is less sun.

On the other hand, the dark pigmentation of eggs, on the contrary, may be more common in southern latitudes, because dark eggs are less likely to attract the attention of predators. As shown earlier, nest predation is more common in warm than in cold climates, suggesting that dark colored eggs are more likely to be laid by tropical bird species. This hypothesis is also supported by the fact that protoporphyrins have antimicrobial properties that are activated by sunlight. The pigments that give eggs their color, especially biliverdin, are also known to protect them from harmful ultraviolet radiation. Therefore, if the color of the eggs has become part of the adaptation to ultraviolet, then in the southern latitudes, eggs of green-blue color should be more common.

To test all these hypotheses, American and Australian ornithologists, led by David Henley (Daniel Hanley) from Long Island University, analyzed the color of 6.7 thousand eggs of 634 species of birds, representatives of 36 out of 40 existing orders. The scientists mapped the nesting range of the birds and looked at how it correlated with the color and brightness of the eggs. In addition, they paid attention to the type of nest and identified three types - open nests on the ground, bowl-shaped nests, and nests located in hollows or depressions. By type of nest, the authors tracked how much sunlight reaches the eggs.

As a result of the analysis, scientists came to the conclusion that color plays the main role in thermoregulation - at least when it comes to cold climates. Darker colored eggs were found in regions with rather cold climates and less sunlight (p< 0.0001).

Distribution of pigmentation in bird eggs

P. Wisocki et al. / Nature Ecology&Evolution, 2019

At the same time, in the tropics and subtropics, color may be influenced by several factors. So, contrary to the assumption of scientists, in areas with a high level of ultraviolet radiation, birds laid light eggs, and dark green-blue ones were found in temperate latitudes, where the level of ultraviolet radiation was lower. Humidity also affected pigmentation: in arid climates, the color of the shell was darker. Interestingly, color and brightness varied the most in hot climates.

As the authors predicted, egg pigmentation also correlated with nest shape (p<0.0001). Виды, делавшие открытые гнезда на земле, откладывали более темные и коричневые яйца, чем птицы, которые устраивали гнезда в дуплах или расщелинах, и те, что вили гнезда в виде чаши. У видов, живших в более прохладном климате и делавших чашеобразные и наземные гнезда, яйца были темнее.

The authors conclude that egg color appears to play an important role in thermoregulation in cold climates. At the same time, since the color and brightness of eggs vary more in southern latitudes, pigmentation in warm climates may depend on several factors.

A few years ago, scientists studied the relationship between the shape of bird eggs and the fitness of birds for flight. In good flyers, the eggs turned out to be asymmetrical, in bad ones, they were round or elliptical in shape.

Ekaterina Rusakova

Thrushes are wonderful small birds belonging to the order of passeriformes, the genus short-beaked. A feature of this bird is its musical, more precisely, singing ability. The appearance of the thrush, as a rule, is not very catchy. The color of the feathers can be a noble brown or light olive with dark brown specks. However, there are also black birds with small bright spots on the tail.

Thrush eggs are painted by nature itself in amazing colors and shades - from blue to light green. Rarely do they have a uniform color. The presence or absence of specks on the eggs indicates that a certain degree of pigmentation is observed in the structure of the eggshell. In the process of egg development, pigmentation is formed due to the concentration of a substance such as protoporphyrin. It is a powerful photosensitizer and contains molecules that can not only absorb the light of sunlight, but also process it into oxygen, light and heat, which are so necessary for the healthy development of chick embryos.

Today in Russia there are 46 species of thrushes. Each species has its own egg color. Thrush of one species is easy to distinguish from another. Differences in the shape, color and pattern of eggs are not radical, but still exist. Thrush eggs, photos of which are presented here, have different color shades, blotches and size. Some are larger and elongated, others are rounded and small. Here are some examples of egg colors.

Swanson's American Thrush has a standard color for all light thrushes, with one difference - the top of the head, tail and wingtips have a reddish tint. His eggs are blue with brown spots. This bird builds nests in the form of a large ball of dried blades of grass. The blue color of the eggs of the American thrush, as well as other species, has always attracted the attention of ornithologists with its brightness. The background blue color is unusual in its shades: greenish, grayish and bright turquoise. And the spots are very clear, brownish-rusty in color. They range in size from microscopic dots to pinhead spots.

Thrush hermit. This bird is very modest, likes to hide from prying eyes among the branches. Its discreet color has more brown color, and a blurry spot is drawn on the chest. Hermit thrush eggs are monophonic, without specks, have a delicate greenish-blue color. The hermit thrush builds nests among the branches of trees so that the sun's rays can reach them as much as possible, nourish them with their light and warmth.

Song Thrush. This population is quite large. The color of the bird is dominated by weak olive and gray shades, with black chocolate-colored speckles. Egg clutch either with dark specks of small size, or color with small brown spots. The dots are often dark chocolate colored. They differ in size: they can be very small spots, or slightly larger - the size of a match head.

Always looks solid, with black plumage, a yellow beak and traced in yellow, orange or rims around the eyes. It differs from other thrushes in larger sizes. Thrush eggs are green in color, close to dark with light brown spots. There are also eggs with a grayish-green background, with larger speckles. On the wide side, each egg is completely colored with brown pigment.