Abstract
Trophic interactions are crucial for maintaining ecological balance. In
cities, avian predation has been shown to be particularly relevant due
to its effects on community structure, pest control, and nutrient
cycling. As humanity relies upon ecosystem services for survival and
70% of the human population is projected to live in cities by 2050,
understanding the effects of urbanization on avian predation is
imperative. This study investigates the effects of urban microclimates,
impacted by impervious surface and green/blue infrastructure, and
human-induced disturbances, on avian predation in urban areas.
Plasticine caterpillars were placed in Quercus robur trees to assess the
avian predation rate. The analyses evaluated the impact of artificial
lighting at night, human population density, noise pollution,
vegetation, and water bodies on predation rates during two months in the
city of Amsterdam. Results indicated a substantial increase in predation
during the second month, likely caused by an increase in naïve
fledglings or elevated ambient temperatures. Noise pollution
consistently emerged as the most reliable predictor of predation,
consistently leading to a reduction in predation rates, possibly due to
avoidance behaviour. Other predictors exhibited substantial temporal and
spatial variability. Artificial lighting at night increased predation in
the first month, suggesting that insectivorous birds predate near
illuminated areas. The diminished effect of artificial lighting in the
second month may be attributed to the increased daylength. During the
second month, all predictors negatively affected predation, supporting
the increasing disturbance hypothesis. These findings underscore the
complex relationship between urban factors and avian predation,
highlighting the need for mitigation efforts in urban planning.