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Trend of the population

Tuesday 23 July 2013, by Julien Lusson

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Global population

The decline of the Corncrake population has been reported since the 19th Century, and has even accelerated in the second half of the 20th century.

Over the past 50 years, the global population appears to have undergone a loss of more than 50 %.

In many areas where the species was once abundant, it has disappeared since the 1980s.

The strongholds of the European population are currently in the countries of Eastern Europe. Whilst the species seemed to prosper during the 1990s, a more recent decline has been noted. In the mid-1990s, the Corncrake had started recovering its population, partly due to the significant reduction of agriculture in former Soviet-Union-dominated countries. This again created suitable conditions for breeding, and resulted in an increase in the global numbers, but this seems to have been only temporary.

Closer to us, an increase in numbers has been noted in several countries where the species had almost disappeared, especially in the British Isles. This happened thanks to the provision and conservation of suitable habitats for the species, including the creation of nature reserves.

**Current trends

During the 1990s, the species increased its numbers in Eastern and Northern European countries, and in Asia. In contrast, this period saw numbers in Western Europe experiencing a significant decline. These opposing trends must be connected with different farming systems within the Corncrake’s breeding area.

French population

**1930 : first data on the distribution of the Corncrake

Although the occurrence of the species is attested in writing in the 17th century, there exists no documented data on the distribution of Corncrake in France before the 1930’s. At that time, the Corncrake was reported breeding in 74 departments, that is to say, in almost all of France except in the three Southern regions : Midi-Pyrénées, Languedoc-Roussillon and Provence-Alpes-Côte d’Azur.

**1950: the beginning of the decline

Ornithological data for the period 1950-1960 no longer mentions the occurrence of the species in certain regions : Brittany, Limousin, Auvergne and Ile-de-France, where it probably disappeared during this period.
At that time, the regions which mainly held Corncrakes were Mid-western, Eastern and Northern France.

**1975-1992 : a drastic decline

The first inventory specific to the Corncrake, conducted from 1982 to 1984, showed that the species did not occur or was strongly reduced on many sites which had still been relatively major during the 1970s, such as the Dordogne valley, Vendée, Sologne, Brenne, Nord-Pas-de-Calais and Somme estuary. Estimates projected from these censuses indicated a population of between 1 600 and 2 200 individuals. Inventories carried out between 1985 and 1989, during the count for the second Atlas of breeding birds, show a national distribution that is quite similar.

The second specific inventory (1991-92), meanwhile, showed a significant decrease in both the numbers and the range of the Corncrake. It vanished from Alsace, Lorraine (where it has reappeared since), and the Alps. The number of calling males was then more than 1 100-1 200, i.e. a decrease of more than 40 % in numbers in less than 10 years.

**1992-1998 : a relative maintenance of numbers

The Corncrake was counted on major sites between 1992 and 1997, within the framework of conservation programmes (LIFE, “Inventaire des ZICO”-IBAs- and followed by agri-environmental measures). These data indicate that the species was still occurring in some sites where it had not been noted in the previous survey, and nearly 90 % of the national numbers were nesting in IBAs, i.e. 1 191 calling males.
In 1998, there were nearly 1 300 calling males mostly concentrated in seven major areas : the Basses Vallées Angevines, the Saône valley, the Loire valley, the alluvial valleys of northern and eastern France, the Charente valley, the Marais Poitevin (Poitou marshes), the Vienne valley (Indre-et-Loire) and Normandy.

**1999-today : the decline

490 to 560 singers were counted at the 4th survey. In 2009, the last year of the plan, the population is maintained at this number: 495-551 singing males. The species continued to decline then : less than 400 singing males counted between 2010 and 2012.