Nest predation pressure differs between urban ground- and hole-nesting birds: evidence from a multi-year artificial nest predation experiment

Some bird species avoid to live in cities, whereas some other species can even thrive in urban settings. One important factor influencing on occurrence, abundance, and success of birds living in cities is nest predation. Urbanization changes nest predator communities, and thereby also nesting success of many species. Hole-nesters and open-cup nesters might differ in vulnerability of nest predation. Because finding of suitable number of nests for statistical analyses, we conducted a multi-year artificial ground nest and nestbox study to analyze effects of urbanization on nest predation pressure. We found that ground nest predation increased with urbanization. In the city, ground nest predation was greater than nestbox predation, whereas nestbox predation was greater than ground nest predation in forests. Ground nest predation decreased with tree cover and increased with the patch area. Our results indicated that ground nesters might avoid urban areas as nesting sites. The results suggest that nest predation is one important factor that could explain, why hole-nesting bird species outnumbered ground-nesting species in cities. The result give support for the hypothesis that nest predation pressure can modify urban bird assemblage structure.