STRAATEN J VAN DER & BERGH LMJ VAN DEN (1970) Distribution of the Corncrake Crex crex in the Netherlands in 1969. LIMOSA 43 (3): 138-151.

Corncrake Crex crex Distribution of the Corncrake (Crex crex) in the Netherlands in 1969 During a night investigation from 1-14 June 1969 a large number of Corncrakes calling was established in the outer marshes of the river Waal, Maas, Rijn, Lek and Gelderse IJssel. Most of the other parts of the country which are suitable for Corncrakes were visited too. 322 Corncrakes were heard in this country, from which 85% along the great rivers. Investigations in the Sliedrechtse Biesbosch proved, that not all Corncrakes are calling in the first decade of June, 50% of them already stopped calling. Because we took the highest of two countings in several cases, most probably the number of Corncrakes should be increased with 30% to get the real number. So some 400 pairs could be taken for the region investigated. In some other regions, not investigated, the presence of Cornrakes is still possible. We suppose that 50 will be the limit. So in 1969 some 450 pair Corncrakes bred in this country. It was possible to compare some countings of 1968 and 1969 from which could be concluded, that some 875 pairs bred in 1968 in this country. Optimal habitat of the Corncrake was found in outer marshes along the great rivers, where each winter the meadows are inundated. But in other places extensive agriculture was important too. This extensive agriculture is also important in the outer marshes of the great rivers. This makes it rather difficult to separate these two factors. The river Maas was an exception. Only 6 Corncrakes were heard here. The breeding-results of the Corncrake are rather bad, mainly owing to the early cutting of hay. If we want to protect the habitat of the Corncrake and of many other scarce birds too, purchasing of the outer marshes of the great rivers is necessary.

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