Preface

Preface:

Milestones of Corncrake Conservation

The Corncrake Crex crex belongs to the few, breeding birds in Europe which are globally threatened (tab. VOGELWELT, S 119). Until some years ago the Corncrake was - compared to other bird species in Germany rather unknown. Gaps concerning the knowledge of its biology and ecology made detailed conservation rather difficult. The lack of information is expressed by FLADE (1991) when writing in the last Corncrake issue of the VOGELWELT (112: 1-116): At that time the question "Do Corncrakes still regularly breed in Central European river valleys?" was not easy to answer.

On 29-30 November 1989 a Corncrake workshop was held by ICBP and the Landesbund für Vogelschutz in Bayern. The aim at that meeting was to describe the gaps concerning biology, status and conservation of the Corncrake. Papers have been published in the above mentioned issue of the VOGELWELT.

Experts coming from many countries had the general opinion that a conservation programme for the Corncrake has to be international because of the population changes from year to year and the high mobility of the species during the breeding season. Conservation programmes focusing on small areas make no sense. The Corncrake is not a species where scientists can get quick exciting results. The secrecy of the species and the difficulty in seeing it, the hidden nests, the problem of proof breeding make it necessary to carry out studies on Corncrakes by experts and scientific teams. Support of amateurs is most welcome" (SOTHMANN 1991). This statement given by Ludwig Sothmann during the workshop in Munich is still completely true.

In October 1994, BirdLife International with financial support of the Royal Society for the Protection of Birds (RSPB) and the European Union (LIFE-Programs) invited Corncrake experts from almost all countries in its range to a workshop aiming at the development of a European-wide conservation programme. This so-called "Action Plan for the Corncrake in Europe" was meanwhile published and is without doubt a milestone in the conservation of the Corncrake (CROCKFORD et al. 1997). During this workshop the International Corncrake Conservation Group was founded.

On 25-26 November 1995 the LBV again invited Corncrake experts from many countries to an international Corncrake Symposium in Freising. The aim was to discuss the recent issues concerning the biology and ecology of the Corncrake. FLADE (1991) listed as most welcome main points for future investigations habitat structure, home range, mobility of the juveniles, moulting habitats, time when leaving the breeding sites, feeding ecology, suitable management of grassland as well as breeding and hatching site fidelity. Many of these points have already been answered.
Results of several recent investigations have been presented to the international Corncrake Symposium in Freising and are published in Corncrake issue of the VOGELWELT (issue 118). Working groups and individuals in Ireland, Scotland, Poland, Germany, Russia, Latvia, Estonia, Romania, Bulgaria, Egypt, Italy, Slovenia, Austria, France, Belgium, Sweden, Czech Republic and Slovakia have thrown more light on the hidden living style of the Corncrake.

Large scale surveys produced a completely new picture of the size of the Corncrake world population (GREEN et al. 1997). The number of calling males for example in Latvia, but most of all in Russia, are much larger than expected until now. Because of this, it has been suggested that the Corncrake be deleted from the list of globally threatened species. But it has to be seen that : Corncrakes are breeding almost exclusively in man-made habitats and therefor are very vulnerable to changes in the management of these habitats; most primary habitats have been destroyed.
Numerous Corncrake populations can be destroyed due to small changes in the management of habitats within a few years as many examples have shown.
The countries in the centre of the distribution (Central and Eastern Europe) due to political and economical changes the agricultural use are changing dramatically at the moment.
The size of the world population was never a reason to list the Corncrake as a globally threatened species. This classification is only based on the criteria "50% decline within the last 20 years". This picture has not changed. We find this dramatic decline in almost all countries where we have detailed longterm data.

In particular, the last point is probably of decisive importance. The extension of changes is shown only by one example: the production of agrochemicals (including pesticides) was reduced from 215.566 t (100%; period 1986-1990) to 51.710 t in the period 1991-1995 (24%), and has been in 1994 only 34.650 t and 1995 only 29.011 t (ANON. 1996). Even more decisive is probably the shortage in fuel for mowing machines. Because of this, large areas have been mown late in the year or not at all, a situation which is extremely good for Corncrakes. In several countries of the former Soviet Union, for example Latvia or Estonia, privatisation of agricultural land was leading to abandonment of large areas. For example in Latvia,according to own data, about half of all meadows have been abandoned in 1996. Bearing in mind that a Corncrake female is able to raise two broods per season with 10 - 12 eggs per clutch, it can be understood, that Corncrake populations within a few years can dramatically increase. In the long term bushes will cover abundant areas, or their management will be intensified, both leading to a negative situation for Corncrakes. This stresses two points: first of all the size of the recent Corncrake population in Central and Eastern European Countries is very difficult to evaluate. On the other hand, the situation can change within a very short time and can turn source populations to sink populations.

During the international Corncrake Symposium in Freising, it became clear, that several questions concerning the biology and ecology of the Corncrake are still not satisfactorily answered and further investigations should be carried out in the future. Important points are:

breeding distribution (not only counting of calling males) in several countries, for example Germany,
divide source and sink populations,
effect of conservation actions,
population trends,
methods of measuring the breeding success,
movement during the breeding season,
ageing and sexing the birds, different voices (investigations only in reasonable aviary conditions)
wintering habitats.

The Corncrake Symposia in Freising was funded by the Bayerischen Staatsministerium für Landesentwicklung und Umweltfragen. We hope that this Symposium was a further milestone in the conservation of the Corncrake.

ANONYMUS 1996: Productional and economical indices of the development of the agricultural complex in Russia in 1995. Moscow. Informagrobusiness: 269 pp.
COLLAR, N. J., M. J. CROSBY & A. J. STATTERSFIELD 1994: Birds to Watch 2 - The World List of Threatened Birds. - BirdLife Conservation Series 4: 1 - 407.
CROCKFORD, N. J., R. E. GREEN, G. ROCAMORA, N. SCHÄFFER, T. J. STOWE & G. M. WILLIAMS 1997: A summary of the European Action Plan for the Corncrake Crex crex.
FLADE, M. 1991: Die Habitate des Wachtelkönigs während der Brutsaison in drei europäischen Stromtälern (Aller, Save, Biebrza). - Vogelwelt 112 (1 - 2): 16 - 39.
GREEN, R. E., G. ROCAMORA & N. SCHÄFFER 1997 Populations, ecology and threats to the Corncrake Crex crex in Europe. Vogelwelt.
SOTHMANN, L. 1991: Editorial - Biologie, Status und Schutz des Wachtelkönigs. Vogelwelt 112: 2-5.