[Working report, 24: Monitoring the birds in agroenvironment 1993 and 1994]

arable soils birds campo censos censuses champ danemark denmark dinamarca environmental impact environmental protection especies farmland fields impact sur l'environnement impacto ambiental monitoring oiseau pesticide pesticides plaguicidas pollution population density protection de l'environnement recensement sol arable species suelos cultivables terre agricole vigilancia