Methodology for surveying the breeding population of water birds in Schleswig-Holstein

Abstract

In order to develop a reliable methodology for conducting a large-scale census of water birds in Schleswig-Holstein, a number of water bodies have been monitored in recent years in accordance with the rules for sample area surveys. Based on the experience gained in the process, the large-scale census is conducted as follows:

1. The aim of the census is to record the families as accurately as possible. Only in the case of great crested grebes, mute swans, coots and moorhens are adult birds included in the determination of the breeding population.

2. In order to record the majority of families of all species, four checks during the main breeding season (for most species from mid-June to the end of July, in early years from the beginning of June to mid-July) are sufficient.

3. All important breeding waters (maximum 170) should be visited at least four times during the main breeding season in a census year. For the less important ones, we can make do with two checks.

4. The maximum number of families recorded in all waters gives the minimum breeding population of a species for the reporting area. The basis of any population estimate must be a precisely verified minimum breeding population of significant size.