In order to study the relation between a bird and a human being in an urban area, we meas ured distance between them at 2 sites when birds staeted a refuge action such as an esca pe action, an evasion, and a caution action. Kokai River was surveyed as a rural river in 1993 and Tama River as an urban river in 1994. The results of measured distance are char acterrized by the following facters.
1. The regional distance (the escape distance at Tama River was shorter than that at Kokai River.)
2. Time difference (the escape distance in 1994 was shorter than that in 1976.)
3. The difference in species character (correlation between a body length and distance, the distribution and location change of the aquaticbirds and urban birds). These results show that an urban area is not always unfavorable habitats for birds, but has a favorable aspect. Therefore we find the possibility of human's coexiatance with birds.