A uniform and general monitoring system does not exist in the Netherlands, despite more than 10 years of discussion on this subject between theoretical scientists and politicians. These discussions were mostly open-ended: scientists developed models for ultimate sampling and stratification, resulting in unfeasible costs; politicians failed to adequately describe their needs in terms of data for policy making and evaluation. Largely independent from these forces, SOVON Birdcensus Work the Netherlands has developed monitoring programmes for birds. SOVON is a private organization, partly funded by the Dutch government and based on an army of volunteers. Comparable organizations exist for other groups of organisms on a smaller scale. Within the constraints of scientific soundness and political applicability, the monitoring by SOVON is growing to maturity. It is obviously the best and most cost-effective alternative for part of the monitoring needs in the Netherlands. With respect to the agricultural bird community SOVON has started to co-operate with some provincial governments that have or will start a provincial breeding bird monitoring scheme in agricultural areas. A stratified sampling strategy is preferred in the study of the impact of condition variables like nature conservation measures, agricultural activities and their interactions. By combining the forces of regional, professional (provinces) and national voluntary (SOVON) networks, a practical, effective monitoring and evaluation can be ensured. The results obtained must be a balanced compromise between methodological problems and financial constraints.