Gruidae

Grus grus

The grunts (Gruidae) are a family of gruiform birds commonly known as cranes. They are birds of open places. They move by striding on their long legs and collect seeds and insects with their long beaks. They live in flocks and many of them travel long distances to breed. They mate for life and have a spectacular courtship display. Males and females strut, bow, and jump quite high. Cranes have very long windpipes and make high-pitched trumpet-like sounds that can be heard up to two kilometers away.

The common crane was once widespread, but its numbers have declined greatly due to the need to live in a quiet habitat. Another crane, which is abundant and very common in zoos due to its showiness and sociability, is the damsel crane (Anthropoides virgo). Cranes are birds that have very long legs and neck, with a long beak, and are endowed with excellent flying abilities, which allow them to make long migrations between breeding areas and wintering areas every year. The legs are provided with three large toes directed forwards and one shorter, backwards. Many species have specially developed feathers with decorative functions. A peculiarity of their anatomy is the length of the extensions of the respiratory system that carry air into the bones, making them very light. These so-called air sacs, in the case of cranes, can reach up to 1.7 meters in length. Cranes usually feed on seeds, berries, roots, fruits and other plant matter, as well as small prey, especially invertebrates.

Species

The Gruidae family includes 15 species grouped into 4 genera:

• Gender Balearica
  • Balearica regulorum
  • Balearic turkey
• Gender Leucogeranus
  • Leucogeranus leucogeranus
• Gender Antigone
  • Antigone canadensis
  • Antigone antigone
  • Antigone rubicunda
  • Antigone vipio
• Gender Grus
  • Grus carunculata
  • Grus paradisea
  • Grus virgo
  • Grus japonensis
  • American Grus
  • Grus grus
  • Grus monacha
  • Grus nigricollis

Behavior and ecology

Common Cranes (Grus grus) in Israel: Many species of cranes meet in large groups during migration and in their winter areas.

Cranes are diurnal birds whose sociality varies by season and location. During the breeding season they are territorial and tend to remain in their territory all the time. In contrast, in the non-breeding season they tend to be gregarious and form large flocks to perch, socialize and, in some species, feed. In South Asia, breeding pairs of sarus cranes maintain territories year-round, and non-breeding birds live in flocks that can also be seen year-round. Large aggregations of cranes likely increase crane safety individual when they rest and fly and also increase the chances that unpaired young birds will find a mate.

Calls and communication

Cranes are very noisy and have several specialized calls. Vocabulary begins shortly after hatching with low-pitched, purring calls to maintain contact with parents, as well as calls for food. When they are chicks they also emit alarm and "flight intention" sounds, which they maintain until adulthood. Cranes are most notable for their loud duet calls which can be used to distinguish individual pairs. Trios of sarus cranes produce synchronized unison calls called "triets" whose structure is identical to the duets of normal couples, but have a lower frequency.

Food

A couple of cuellinegras cranes (Grus nigricollis) feeding.

Cranes eat a wide variety of foods, both animal and plant. When feeding on land, they consume seeds, leaves, nuts and acorns, berries, fruits, insects, worms, snails, small reptiles, mammals, and birds. In wetlands and agricultural fields, they also consume roots, rhizomes, tubers, and other parts of emergent plants, other mollusks, small fish, bird eggs, and amphibians^{[citation needed]} The The exact composition of the diet varies by location, season, and availability. Within the wide range of items consumed, some patterns are suggested, but specific research is required to confirm them; shorter-beaked species tend to feed in drier uplands, while longer-beaked species feed in wetlands.

Cranes use different foraging techniques for different types of food and in different habitats. Cranes dig for tubers and rhizomes and remain in place for some time digging and then enlarging a hole to pull them out of the ground. Unlike this and the stationary hunting methods employed by many herons, they search for insect and animal prey by moving slowly forward with their heads lowered and feeling with their bills.

When there is more than one species of crane in a locality, each of them adopts separate niches to minimize competition. In a major lake in the Chinese province of Jiangxi, Siberian cranes feed in mudflats and shallow water, white-necked cranes at the edges of wetlands, hooded cranes in reed meadows, and the last two species are they also forage in agricultural fields along with common cranes. In Australia, where sarus cranes coexist with brolgas, they have different diets: The sarus cranes' diet consisted of diverse vegetation, while the brolgas' diet spanned a wide range. much broader range of trophic levels. Some crane species, such as the Eurasian/Eurasian crane, use a kleptoparasitic strategy to recover from temporary reductions in feeding rate, particularly when the rate is below the intake threshold necessary for feeding. survival.

The accumulated intake during the day shows a typical antisigmoid form, with greater intake increases after sunrise and before dusk.

Iconology

This animal was among the ancients one of the symbols of prudence and vigilance.

According to naturalists, when cranes arrive somewhere, they lay in wait so as not to be surprised by sleep; The bird stands on only one foot and has a stone on the other, so that when it falls it will wake it up. He has been given surveillance by attribute. It is said in Japan and China that cranes are equivalent to a lucky charm.

The crane has entered many companies. When she acts as a sentinel, while the others sleep, with this nickname: Nihit me stante timendum, it is the motto of a vigilant chief. When they fly, according to their custom, under the direction of only one, with this hemistich: omna directit una, it can be applied to a prince whose conduct the peoples follow. A crane that, foreseeing an impetuous wind, loads itself with a stone, with these words: Firmal gravitote volalum means that the maturity of judgment ensures the company. They have been given for currency to a republic where each one in his turn can obtain the first degree in the government the cranes that lead each one in turn, with these words: Alternis agmina ducunt . Cranes, as well as eagles and vultures, go through favorable omens.

The thousand cranes

Paper cranes made by Japanese children in homage to Sadako, placed before its monument in Hiroshima.

In the XX century, origami in the shape of a crane became popular as a wish to restore the health of a sick person and as a tribute to those who die violently.