Spatial imprinting of fear: Escape behavior of birds across a small human activity gradient

Between September and November 2024, data collection was carried out in the Liuzi Special District (105°28′38″ E, 26°12′52″ N) of Liupanshui City, Guizhou Province, southwest China, and in the Southern Breeding Base of the Lingshui County, Hainan Province (108°59′22″ E, 18°27′06″ N), south China. These two time periods corresponded to the local maturity stage of rice in the two respective study sites. In both sampled sites, one village and its surrounding rice fields (Figure 1a, b) were selected for experimentation. During the experimental period, the rice fields were at the mature stage and human activities involved driving away birds (mainly Eurasian tree sparrows (Passer montanus) that came to forage for food (Video S1). Although humans were able to access the rice fields, not all areas were accessible due to terrain constraints. During experiments in the selected villages, we found that both villages had large, open rice-drying yards (Figure 1c), which differed from the environments of both the village and rice field with respect to accessibility and deterrent measures. Fieldwork revealed that human behavior towards Eurasian tree sparrows differed across these three areas (Zhao et al., 2024). Hence, we divided the experimental sites into three areas: rice field, village, and drying yard (Figure 1).The results showed that: (1) The spatial pattern of sparrow FIDs was consistent between the two study sites (drying yard > rice field > village), indicating that this species was able to fine-tune its tolerance thresholds for risk based on human activities (e.g. presence of deterrence). Furthermore, historically established hunting pressure may still exert long-term effects on the vigilance of sparrows. (2) FID differences among the three sampling areas in Lingshui were highly significant, whereas differences between drying yards and rice fields were not significant in Liuzhi. This suggests that latitude-driven environmental filtering may amplify local behavioral plasticity, but more evidence is needed to verify this claim. (3) FID was positively correlated with flock size, supporting the early-warning hypothesis. Our study elucidated the role of microhabitat heterogeneity within rural areas in regulating avian anti-predator strategies, thus providing a new perspective for understanding the mechanisms underlying behavioral adaptations in human-bird coexistence, and highlighting the long-term impact of human activities on avian behavior.