1. This paper describes the formation of basic flocks, particularly the movement of the young from the dispersal to the final settlement in a restricted area, and discusses the factors relating with the association of members in a basic flock. The field work was carried out in the summer and autumn of 1970 at the Akasaka Palace, Tokyo, Japan. The study area of about 37ha consisted of mixed evergreen and deciduous broad-leaved forest. In the study area, virtually all of the birds were marked individually by colour rings and their previous history was known. 2. The formation of the basic flocks took place through a successive process; the establishment of summer and autumn ranges of young, and the final association of the young and adults in an area. The young were associated with each other to form the summer flock when the family flocks broke up. Most of the young established their summer range within a relatively short period, usually about a month, after having become independent of their parents. 3. Forming the summer flocks, the young gradually showed a preference for a particular part of their summer range. The number and members of young observed in the same area became more and more constant from this time onward. By the middle of October, most of the young established the autumn range within their summer range. It is considered that the young establish their summer or autumn ranges within the home range of their family flock. 4. The adults remained on or near their previous breeding territory even after the breeding, and then the young settled in the area as the autumn range. Consequently, the home ranges of the adults and the autumn ranges of the young overlapped extensively as a whole. And a basic flock was formed by these birds. Therefore, it is concluded that the formation of basic flocks are closely related with the period of the extensive overlap of home ranges between individuals, and that the members of a basic flock are primarily associated with each other by their site attachment.
1. This paper describes home range of the basic flocks and the dominance relationship between the members of a basic flock, and attempts to clarify the structure, size and basic of home range and the factors affecting dominance relationship of the members in a basic flock. 2. The field work was made from the spring of 1968 to the winter of 1974-75 in the Akasaka Palace, Tokyo, Japan. The study area of about 37ha mainly consisted of mixed evergreen and deciduous broad-leaved forest. Virtually all of the birds were marked individually by colour rings and their previous history was known. 3. The home range of the basic flock can be divided into two area. The first is a main area in which the basic flock foraged over by itself. The second is a secondary area in which the flock moved about with other flocks as compound flock. The size of home range was, in average, 5.5±2.5ha, ranging from 0.7 to 15.9ha. 4. The main area is called "basic flock range". The basic flock range can be also divided into two parts; a central part and a peripheral part. The central part was more favourable feeding area than the peripheral one and contained a feeding activity center as most favourable feeding place. 5. The basic flock ranges overlapped each other extensively and were not defended against encroachment of neighbouring flocks. But they were well defined throughout winter and the feeding activity center of neighbouring flocks never overlapped each other. 6. The size of basic flock ranges varied from 0.5 to 3.9ha, with an average of 1.6±0.6ha. It was closely related with the number of adult males in the flock since the basic flock range was based on the previous breeding territories of adult males belonging to the flock. 7. In the process of flock formation, adults remained their domiciles even after breeding, and then young select the area as their domicile. Therefore, it is concluded that the basic flock consisted of individuals whose domiciles overlapped and the basic flock range was the overlapping range of domiciles between members of the flock. 8. Adults always dominated over young within a sex group. The important factor determining the dominance relationship was the prior occupancy of the basic flock range in adults. Males always dominated over females within an age group. This was due to more aggressiveness and larger body size of males. 9. The dominance relationship of young within a sex group seemed to be determined before the formation of the basic flock and remained stable after the flock were formed. The prior occupancy of the basic flock range and body size were probably important to determine the dominance relationship. 10. Adult males were always dominant to young females. This was due to the adult's prior occupancy of the basic flock range and the dominance of the sex. The dominance relationship between adult females and young males was not unilateral as a whole, but that between a particular adult female and a particular young male was linear and unilateral in a basic flock. The factor affecting such relation was unknown. 11. Although the dominance relationship of adults within a sex group was site dependent, most of the basic flocks contained one adult male and/or one female and the dominance relationship was linear and unilateral. The relationship was maintained throughout winter and stable over the basic flock range. 12. Taking the dominance relationship into consideration, it is certain that the members of a basic flock recognized each other individually. The association of members primarily based on the overlap of their domiciles has to be solidified by the individual recognition between the members.
1. This paper describes the pair formation and establishment of territory in the members of basic flock and attempts to clarify the factors determining mate selection and arrangement of territories of flock members within the basic flock range. 2. The field work was made from the spring of 1968 to the winter of 1974-75 in the Akasaka Palace, Tokyo, Japan. The study area of about 37 ha mainly consisted of mixed evergreen and deciduous broad-leaved forest. Virtually all of the birds were marked individually by colour rings and their previous history was known. 3. Pair formation took place after the basic flocks broke up in spring. Both mates of previous breeding pairs re-paired with each other as long as they survived in the following spring. As the pair-bond broke up after breeding, re-pairing of previous breeding pairs was basically not different from new pairing of widowed adults or young. 4. The members of a basic flock primarily paired with the other members of the flock. Since the domiciles of members in a basic flock overlapped extensively, it is concluded that the overlap of domiciles plays an important role in the pair formation; pair formation takes place between individuals whose domiciles overlap. 5. The pairs were spaced out with their territory after the basic flocks broke up. Most of the members in a basic flock established their territory within the basic flock range which contained all domiciles of the members. All of the adult males and most of the young males held their territory in the central part of the flock range, but some young males were forced to establish their territory in the peripheral part and a few ones were forced to disperse from their basic flock range. 6. When a more favourable area became vacant as a result of the death of the owner during autumn and winter, a surviving adult first occupied there, and then another male, usually young, established the territory in the vacant area after the adult male moved into the favourable area. When the flock contained only one adult male and the male died during winter, young male occupied the previous breeding territory of the adult male in the following spring. 7. Thus adult males dominated over young males in the establishment of territory within the basic flock range. Although the males established their territory within their domicile, the domiciles of adult and young males overlapped extensively. The adult males selected the area as domicile at least one year earlier than the young males, so the prior occupancy of adult males is important to determine the arrangement of territories within the basic flock range. 8. Therefore, it is concluded that the overlap of domiciles and the prior occupancy of an area play the important role in the social organization of the breeding season, like that of the non-breeding season in the Great Tit.
1. In the neighbourhood of Kyoto City where resident minor breed, migratory minor andkawarahiba immigrate in non-breeding season. To make clear the inter relation among them, observations were carried out. 2. Resident minor show high sedentariness in the forest fringe throughout winter. Most of them were pair already in winter. They form loose flocks and continuous joining and leaving are observed. They have several types of feeding grounds such as paddy fields, vegetable fields, forests, etc., so their food contents were very different individually. 3. Migratory minor form large and well-integrated flocks in the open land, and all of them feed on restricted kind of food available at a single feeding ground. They roost communally. The body size is a little larger than that of resident minor. 4. Migratory kawarahiba are observed mainly in autumn and early spring. Their feeding habitat, the state of flock, food content, roost, etc. are similar to those of migratory minor. 5. From the observations of movements, sedentariness and disappearence of many individually marked birds, it was confirmed that the flocks formed by the mingling of the birds of these groups are rare and most birds of the three groups live in segregation in habitat or season. The following matters have also been confirmed: resident minor show strong trend to stay close to their breeding areas already in winter; migratory minor have also relatively high sedentariness in the open land in winter; the flocks of kawarahiba which stop off in the open land are changing it's members in a short period. 6. Short-period observations at Higashi-kushira and Kumamoto in Kyushu confirmed that in the former area resident minor lived near forest, while migratory kawarahiba open field, however, in the latter area where there was no minor, kawarahiba used widely from the seaside to the paddy field just near forest. 7. Discussion was made about the mechanism of the segregation of these three populations. The sedentariness of resident minor in the forest fringe is closely related with the situation that most of them pair, while those two migratory groups live in the open land seem to be related to food made available temporarily in large quantity. In addition to this, the interactive relation must play an important rele in their spatial segregation in habitat.