1982 年 14 巻 2-3 号 p. 306-324
Since 1977, mating behaviour of the Yellow-breasted Bunting Emberiza aureola had been observed in a small area of peat lands in Ishikari Plain, central Hokkaido, northern Japan. About 36 bouts of mating behaviour were recorded. The copulation attempts usually occur on the ground during June and July. The postures and movements making up the sequence of mating behaviour are: wing-raising, tail-fanning-walk, ordinary approach, arching (female), mounting, copulation, head-up-lie-flat (male), extrication (male), material carrying, etc. Various sequences of mating behaviour are tentatively grouped in two categories. One is the simple type, usually occurring in three units: "gathering", "movements toward female", and "copulatory acts". The other is a more intricate sequence, with "his wing raising before her landing", "reversal display", and "carrying material". The primary difference between these two categories of behaviour depends on whether or not the male gives the head-up-lie-flat (reversal display) after copulation. The appearance of this specific behaviour seems to be related to the presence or absence of the male's tail-fanning-walk toward the female before copulation attempts. This tail-fanning-walk which precedes mounting may involve both tendencies to stay before female and avoid her, and induces the head-up-lie-flat behaviour. This possibly decreases her tendency to flee.