SOVON (1985) Cooperating Organizations Bird Research Netherlands. Design and implementation. LIMOSA 58 (4): 168-168.

Identifying and understanding changes in the breeding position on a national scale is usually not simple and can take years sams whey. to Although in many places were now breeding bird surveys performed, but the way this happened differed. This allows data of the areas are difficult to compare. Oak are birders who regularly field inventory and also determine an increase or decrease. They rarely come out if their results reflects what is happening elsewhere in the country occurs or that it is a local phenomenon they identify. We want some changes best possible mapping will be necessary roughly equivalent to annual data Yen on the table. The only feasible way is an annual fixed number of sample areas (plots) always in the same way inventory. This requires tight arrangements and a clear standardization. In addition, that the greater the number of inventoried plots, ofweI more observers, more species can be monitored. Calculations of the scientific supervisory showed annually at least 60 plots with a combined area of ​​at least 4000 ha under Locht Louden must be to a national monitoring project succeed. It is then possible pm from 30 to 40 common species reliable statements.

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