Escape behavior and refuge selection preferences by two common urban birds

Urbanization destroys wildlife habitats, fragmenting them into small patches with poor connectivity, leading to population declines in species sensitive to such changes. Escape is the most common anti-predator strategy adopted by birds, refuges in habitats reduce or eliminate predation risk. Therefore, creating habitats with suitable refuges for birds has significant implications for their conservation. However, there have been few studies on refuge selection in birds. This study examined the Eurasian Tree Sparrow (Passer montanus) and Oriental Magpie (Pica serica) in urban and rural areas of Chengde City, northern China by measuring their alert distance (AD), flight initiation distance (FID), and distance fled (DF) and analyzed their refuge selection characteristics after escaping. The FID/AD ratio was employed to assess the behavioral differences of birds in the risk trade-off. The results showed that the FID and FID/AD of both species were lower in urban areas than in rural areas and were negatively correlated with immediate human density. Sparrow FID was significantly affected by group size and landing substrate type. The FID of sparrows was positively correlated with the group size. The sparrows that fled to bushes escaped earlier. In urban and rural areas, sparrows exhibited significantly lower FID, DF, and FID/AD than magpies. The species adopted different refuge selection strategies, with magpies preferentially selecting trees with greater vertical height and sparrows selecting both trees and bushes. Further analysis indicated that the horizontal and vertical distances fled of both species were lower when fleeing to bushes. Urban planning and conservation areas construction should incorporate the ecological needs of local bird species to rationally configure their habitat structure, thereby optimizing the effect of avian conservation.