Abstract
Studies on the social behavior, territory, and pair duration of Japanese Wagtail Motacilla grandis were carried out from October 1978 to March 1981 at Utsunomiya, Tochigi Prefecture, central Honshu. Most observations were made on colour-ringed birds. The results obtained were as follows:
1) The territorial behavior of Japanese Wagtails observed in the study area consisted mainly of chasing, ceremonial fight and combat (Fig. 2). The displays between a male and a female were female's appeasement display and male's bill-opening display.
2) Most of Japanese Wagtails lived in pairs and each pair had a definite territory in winter. There was little change in the location of territories and in the mates of pairs from October to January.
3) In February some changes were found in territories and mates, i.e. nine out of eleven pairs changed their mates. The mating season was generally from late February to early March.
4) In winter 10-20 individuals gathered for feeding in the temporary dried up areas. No territorial behavior was seen in such feeding place. Some of them had their territories outside of the feeding place, whereas others had no territories and were wandering from one place to another.
