Who gains and who loses - the impact of maize cultivation on breeding birds in central Europe

Many European countries are experiencing a decline in the breeding birds populations, which are one of the main indicators of changes in biodiversity, due to the intensification of agriculture. Maize deserves particular attention in this regard, as research on the impact of this crop on breeding bird species in Europe is scarce. This study focused on examining the impact of maize cultivation on the species richness and density of breeding bird species in agricultural landscapes in Poland. The research was conducted during the breeding seasons (April-June) in 2024 and 2025 in maize fields and control plots, which were mosaics of other types of cultivation. A total of 122 plots with a total area of 1380 ha were inspected in three regions of Poland. Both species richness and density of breeding birds were significantly lower in the maize fields compared to the control plots. Of all the breeding bird species recorded, skylark, corn bunting, yellow wagtail, and pheasant showed a negative correlation, while the white wagtail and lapwing showed a positive correlation with maize cultivation. Additional analyses on data from control plots showed that the species richness of breeding birds increased with the number of crop types comprising a given plot. Despite the positive impact on some species, maize cultivation generally had a negative effect on breeding bird species in agricultural landscapes. In order to preserve farmland biodiversity, maize sowing should be limited, the number of crop types should be maintained at a high level, and environmental heterogeneity should be preserved.