Pan European Cormorant Midwinter Census (Item 2)

During the 5th International Conference of the Wetlands International Cormorant Research Group held in Germany the idea of organizing and carrying out a Pan European Cormorant Midwinter census was born. The strong increase and the development of cormorant breeding colonies is well documented in many European countries, in contrast, not enough information about the actual situation of the migrating and wintering population of Great Cormorants in Europe exist.
The aim of a pan European census is to get a picture about the actual population size, migration pattern and distribution of cormorants in Europe as complete as possible. To reach that goal we would like to take advantage of the experience of people joining the existing international water-bird census network as volunteers in many European countries. The plan is to count all cormorant night roosts (inland and sea coasts) in all European countries and North Africa in mid January 2003.

How to count great cormorants in winter?
In contrast to the practice of the international water-birds counts taking place during daytime cormorants counts have to be made by controlling roost sites in the late afternoon. Ideally, counts should take place at the end of the day about two hours before dusk or at dawn. To avoid double counts, cormorants should not be counted during daytime on their feeding grounds or on their day roosts. Cormorants are highly mobile birds used to flying over longer distances (> 40-60km) between night roosts and feeding grounds. Numbers of cormorants counted during the daylight activity can not be used for summing up counts to get a total result on a national level and finally will not give an adequate estimate for the overall European population size. So it is necessary to organize and carry out coordinated simultaneous night-roost counts.

Counting date:
Following the recommendations to collect data about water-bird populations on an international level, we choose as counting date the 15th of January or the preceding weekend:
First (preferred) counting date: 15 January 2003 or weekend 11/12 January 2003
Alternate date: following weekend 18/19 January 2003).
Please pay attention to the fact that on adjacent locations within an area or region where shifts of cormorant flocks between roost sites may occur frequently, simultaneous counts on the same date should be coordinated on a national level to assure accurate counting results.
Methodology:
1. Two European coordinators have been named to be responsible for contacting potential national coordinators in every country (name of coordinators and relevant list of countries see below). To build up contacts support will be given by members of Wetlands International.
2. On a national level identification of relevant roosting sites in every country is necessary (big cormorant roost sites are often well known due to research projects, official winter counts or various national reports), list of relevant roost sites with geographical coordinates should be available.
3. A national coordinator in every country is organizing a national counting team. One person for every location/roost site is needed to count cormorants being present (simultaneous counting date!).
Protocols:
4. Use standard forms for counts, either European form or adapted national form for every country according to their specificity. The European Form will be distributed in advance by the European coordinators, instructions about details or notes which should be taken and written down on the formsheets will be sent out together with counting forms.
For summing up data collected on a national level to get a Pan European census result, the following basic information from every roost-site count is essential:
o Date and hour of count
o Name of observer (on specific location)
o Name of national coordinator
o Name of locality (plus name of department or province, geographical coordinates, position of roost
sites should be indicated on a joined map of the roosts at a regional scale)
o Total number of Cormorants being present (at the end of observation time)
5. The national coordinators should make collection, summing-up and analysis of counting results in every country. The total number of wintering Great Cormorants and the national map of the distribution of the roosts should be addressed to the two European coordinators, Dr. Loïc Marion for North-West Europe and Dr. Rosemarie Parz-Gollner for Central Europe, who will finally realise the European synthesis.


Dr. Loïc MARION
Laboratoire d'Evolution des Systèmes Naturel & Modifiés,
Univ. of Rennes,
Campus Beaulieu;
35042 RENNES cedex, France.
Tel. (+33) 2 23 23 61 44 Tel. (+43) 01 47654-4453
e-mail: Loic.Marion@univ-rennes1.fr

Dr.Rosemarie PARZ-GOLLNER
Institute of Wildlife Biology and Game
Management, Univ. of Agricultural Sciences Vienna;
Peter Jordanstrasse 76,
A-1190 VIENNA, Austria
Fax (+33) 2 23 23 51 38 Fax (+43) 01 47654-4459
e-mail: parz@mail.boku.ac.at

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