The map demonstrates the relationship between population density and sparrow counts in 88 routes covering 18 districts. All routes are about 1 kilometer long. It shows that areas with higher population density tends to associate with more sparrows. For example, in the Kowloon districts, Sham Shui Po, Wong Tai Sin, and Kwun Tong are crowded areas (with darker shading). These districts also have comparatively darker lines, representing higher sparrow count. Counter-intuitively, Yuen Long District, where a major nature reserve is homed, has fewer sparrows. Yuen Long, at the same time, has a lower population density. The results shows that more populous residential areas somehow attract more sparrows to stay, hinting at a symbiotic relationship between sparrows and humans.