Thursday 14 March 2013
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The Corncrake only breeds in Eurasia. It is distributed from the Atlantic to the heart of Siberia, and from Scandinavia in the North to areas around the Black Sea in the South.
More than 90 % of the population nests in Asia (Russia, Georgia, Iran, Afghanistan, Tajikistan, Kazakhstan and China). Its distribution in Western Europe is much more fragmented, and limited in most cases to only a few well-preserved alluvial valleys.
Behaviour during the breeding season
In spring, the male tries to attract a female with specific courtship behaviour. Head up, he emphatically repeats his grating "krek krek" call. The female is attracted by these monotonous calls and approaches. The male then immediately begins to display, strutting and showing off the scale pattern on his wings.
The male will stay near the female for a few days, during which time he remains silent.
The female then lays between 8 and 12 eggs in a newly formed, simple nest on the ground. She incubates and cares for the chicks without help from the male. The young hatch after two weeks and are fed by their mother for two or three days. They then find their own food, but stay with their mother for about twelve days. Once the young are independent, the female may lay a second clutch. The chicks fledge when about a month old.
There is little information regarding the Corncrake’s population dynamics.
From a study in the British Isles, year to year survival would be 20 to 30 %, both for fledged young and adults. Adult survival being low, the species’ population dynamics are strongly influenced by the productivity of young birds.
Otherwise, in the British Isles, it has been shown that second broods tend to be more productive. Management measures that allow the Corncrake to complete this second breeding cycle have led to a 25 % increase in the production of fully-fledged chicks. This highlights the significance of maintaining unmowed plots later in the summer, when second broods are likely to arrive at the fledging stage.