Foraging Tactics and Dietary Habits of Red-vented Bulbul (Pycnonotus cafer stanfordi Deignan) and Their Impact on Fruit Crops: A Field Case Study

Seasonal variation in avian foraging behaviour can significantly influence crop depredation in agro-ecosystems, yet quantitative assessments linking seasonality, dietary shifts, and crop damage remain limited. Field observations were conducted across seasons to examine roosting behaviour, daily foraging patterns, dietary intake, and crop damage to three economically important fruit crops: guava, papaya, and banana. During the non-breeding season, bulbuls formed communal roosts and exhibited a bimodal foraging pattern, with activity peaks occurring 1–2 hours before sunrise and again during late afternoon. In contrast, during spring and summer, these patterns were disrupted, and birds foraged solitarily or in pairs in multiple short bouts, reflecting seasonal behavioural plasticity. Dietary analysis revealed a season-dependent shift between plant and animal food resources. Plant-based diets peaked at 79.14 ± 1.69% in February and declined to 56.73 ± 2.30% in August, whereas animal-based diets increased correspondingly, reaching 43.27 ± 2.30% in August. Insect consumption was significantly higher during the monsoon period (June–September) compared to other months. Controlled field assessments demonstrated measurable economic impacts on fruit crops, with estimated damages of 6.79% in banana, 13.10% in papaya, and 17.67% in guava of total yield. The findings indicate that seasonal resource availability and physiological demands influence bulbul foraging strategies, which in turn determine the extent of crop depredation. This study provides empirical evidence linking avian behavioural ecology with seasonal crop loss, offering insights relevant to avian pest management and agro-ecosystem conservation strategies.