Editing Common crane (section)

==Behaviour==

===Diet===
The common crane is [[omnivorous]], as are all cranes. It largely eats plant matter, including [[root]]s, [[rhizome]]s, [[tuber]]s, [[Plant stem|stem]]s, [[leaf|leaves]], [[fruit]]s and [[seed]]s. They also commonly eat, when available, pond-weeds, [[Heath|heath berries]], [[pea]]s, [[potato]]es, [[olive]]s, [[acorn]]s, [[Cedrus|cedar nuts]] and pods of [[peanut]]s. Notably amongst the berries consumed, the [[cranberry]], is possibly named after the species.<ref>{{Cite web |last=Harper |first=Douglas |date=4 May 2018 |title=Cranberry (n.) |url=https://www.etymonline.com/word/cranberry |access-date=26 January 2024 |website=Online Etymology Dictionary}}</ref>

Animal foods become more important during the summer breeding season and may be the primary food source at that time of year, especially while regurgitating to young. Their animal foods are [[insect]]s, especially [[dragonflies]], and also [[snail]]s, [[earthworm]]s, [[crab]]s, [[spider]]s, [[millipede]]s, [[woodlice]], [[amphibian]]s, [[rodent]]s, and small [[bird]]s.

Common cranes may either forage on land or in shallow water, probing around with their bills for any edible organism. Although crops may locally be damaged by the species, they mostly consume waste grain in winter from previously harvested fields and so actually benefit farmers by cleaning fields for use in the following year.<ref name=Alonso1994/> As with other cranes, all foraging (as well as drinking and roosting) is done in small groups, which may variously consist of pairs, family groups or winter flocks.

===Breeding===
[[File:PSM V09 D158 Crane throat structure.jpg|thumb|The long coiled [[Vertebrate trachea|trachea]] (TR) penetrating the [[Keel (bird anatomy)|sternum]] (S, K, A) produces the trumpeting calls of the crane. L on the left - [[Lung#Avian_lungs#Avian lungs|lungs]], LA - [[larynx]], L on the right - [[tongue]].]]
This species usually lays eggs in May, though seldom will do so earlier or later. Like most cranes, this species displays indefinite monogamous pair bonds. If one mate dies, a crane may attempt to court a new mate the following year. Although a pair may be together for many years, the courtship rituals of the species are enacted by every pair each spring. The dancing of common cranes has complex, social meanings and may occur at almost any time of year. Dancing may include bobs, bows, pirouettes, and stops, as in various crane species. Aggressive displays may include ruffled wing feathers, throwing vegetation in the air and pointing the bare red patch on their heads at each other. Courtship displays begin with a male following the female in a stately, march-like walk. The unison call, consists of the female holding her head up and gradually lowering down as she calls out. The female calls out a high note and then the male follows with a longer scream in a similar posture. Copulation consists of a similar, dramatic display.

<gallery mode="packed" heights="150px">
File:Baltsende en parende kraanvogels-Stichting Natuurbeelden-170687.webm|pair showing the mating behavior
Grus grus egg - Niitvälja bog.jpg|Egg on nest
Common crane chick swimming alone on the Tidan River, Sweden.jpg|Chick on the [[Tidan|Tidan River]], Sweden
Common crane (Grus grus) juvenile Oppdal.jpg|Juvenile in [[Norway]], showing developing adult plumage
</gallery>

The nesting territory of common cranes is variable and is based on the local habitat. It can range in size from variously {{convert|2|to|500|ha|acre|abbr=on}}. In common with sandhill cranes (and no other crane species), common cranes "paint" their bodies with mud or decaying vegetation, apparently in order to blend into their nesting environment. The nest is either in or very near shallow water, often with dense shore vegetation nearby, and may be used over several years. The size and placement of the nest varies considerably over the range, with Arctic birds building relatively small nests. In Sweden, an average nest is around {{convert|90|cm|in|abbr=on}} across.

The clutch of the common crane usually contains two eggs, with seldom one laid and, even more rarely, 3 or 4. If a clutch is lost early in incubation, the cranes may be able to lay another one within a couple of weeks. The incubation period is around 30 days and is done primarily by the female but occasionally by both sexes. If humans approach the nest both parents may engage in a [[distraction display]] but known ground predators (including [[Dog|domestic dogs]] (''Canis lupus familiaris'')) are physically attacked almost immediately.

New hatchlings are generally quite helpless but are able to crawl away from danger within a few hours, can swim soon after hatching and can run with their parents at 24 hours old. Chicks respond to danger by freezing, using their camouflaged brownish down to defend them beyond their fierce parents. Young chicks use their wings to stabilise them while running, while by 9 weeks of age they can fly short distances. The adult birds go through their postbreeding moult while caring for their young, rendering them flightless for about 5 to 6 weeks around the time the young also can't fly yet. According to figures of cranes wintering in Spain, around 48% birds have surviving young by the time they winter and around 18% are leading two young by winter. By the next breeding season, the previous years young often flock together. The age of sexual maturity in wild birds has been estimated at variously from 3 to 6 years of age.

===Longevity===
This species could live up to 30 or 40 years of age.<ref name=Burton2002/> But the data on [[longevity]] (43 years) and [[life expectancy]] (12 years, N=7 cranes) were published with captive cranes.<ref name=Mitchell1911/> Common cranes living in the wild must show shorter lives. Successful breeders, the best subjects in the population, are guessed to live on average 12 years.<ref name=Wessling2021/> Unsuccessful breeding cranes, therefore, may have shorter lives. Elementary [[survival analysis]] with the Euring database<ref name=Euring2018/> reports a life expectancy at birth (LEB) of c. 5 years.<ref name=Bautista2021/> This LEB of 5 years was similar to that estimated for other crane species, as for example the Florida [[sandhill cranes]] (''G. canadensis'') (LEB = 7 years).<ref name=Tacha1992/> Reports of tagged common cranes have increased rapidly in the last decades.<ref name=iCORA2018/> Therefore, longevity and life expectancy at birth of wild common cranes will be updated.

===Sociality===
The common crane is a fairly social bird while not breeding. Flocks of up to 400 birds may be seen flying together during migration. Staging sites, where migrating birds gather to rest and feed in the middle of their migration, may witness thousands of cranes gathering at once. However, the flocks of the species are not stable social units but rather groups that ensure greater safety in numbers and collectively draw each other's attention to ideal foraging and roosting sites.<ref name=Bautista1995/> Possibly due to a longer molt, younger and non-breeding cranes are usually the earliest fall migrants and may band together at that time of year. During these migratory flights, common cranes have been known to fly at altitudes of up to {{convert|33000|ft|m|abbr=on}}, one of the highest of any species of bird, second only to the [[Ruppell's Griffin Vulture]].<ref>{{cite web|url=https://themysteriousworld.com/10-highest-flying-birds-in-the-world/|title=Top 10 Highest Flying Birds In The World - The Mysterious World|date=31 March 2015}}</ref>

Cranes use a kleptoparasitic strategy to recover from temporary reductions in feeding rate, particularly when the rate is below the threshold of intake necessary for survival.<ref name=Bautista1998/> Accumulated intake of common cranes during daytime at a site of stopover and wintering shows a typical anti-sigmoid shape, with greatest increases of intake after dawn and before dusk.<ref name=Bautista2013/>

===Interspecies interactions===
There are few natural predators of adult cranes, although [[white-tailed eagle]] (''Haliaeetus albicilla''), [[Bonelli's eagle]]s (''Aquila fasciata''), [[eastern imperial eagle]]s (''Aquila heliaca'') and [[golden eagle]]s (''Aquila chrysaetos'') are a potential predatory threat to common cranes of all ages.<ref name=Moll1963/><ref name=Sulkava1984/><ref name=Munoz-Pulido1993/><ref name=Aviles1998/><ref>Horváth, M., Solti, B., Fatér, I., Juhász, T., HaraSztHy, L., Szitta, T. & Pásztory-Kovács, S. (2018). Temporal changes in the diet composition of the Eastern Imperial Eagle in Hungary. Ornis Hungarica, 26(1), 1-26.</ref> The crane has been known to counterattack eagles both on the land and in mid-flight, using their bill as a weapon and kicking with their feet.<ref name=Johnsgard1983/> Mammals such as [[wild boar]] (''Sus scrofa''), [[wolverine]] (''Gulo gulo'') and [[red fox]]es (''Vulpes vulpes'') are attacked at the nest. Herbivorous mammals such as [[red deer]] (''Cervus elaphus'') may also be attacked at the nest, indicating the high aggressiveness of the birds while nesting.<ref name=Johnsgard1983/> The determined attack of a parent crane often assures safety from predators including large mammals such as foxes, but occasional losses to predation are inevitable.<ref>Stanbury, Andrew, and Norman Sills. "Common crane habitats in Britain." British Wildlife 23.6 (2012): 381.</ref> The [[carrion crow]] (''Corvus corone'') is locally a successful predator of common cranes' eggs, trickily using distraction displays to steal them. Other species of ''[[Corvus (genus)|Corvus]]'' may also cause some loss of eggs, with [[common raven]]s (''Corvus corax'') also taking some small chicks.<ref name=EOL/><ref name=Leito2005/> Common cranes may loosely associate with any other crane in the genus ''Grus'' in migration or winter as well as [[greater white-fronted goose|greater white-fronted geese]] and [[bean goose|bean geese]].<ref name=Johnsgard1983/>