Home Range and Pair Duration in the Varied Tit Parus varius

Abstract

An investigation of home range, territory, and pair duration in the varied tit (Parus varius) was conducted on the Izu Peninsula (mainland) and on Miyake I. of the Izu Is. from April 1972 to June 1975. Most observations were made on colour-ringed birds. The results obtained were as follows: 1) Most of the varied tits lived in pairs throughout the year in the Izu Peninsula. On Miyake I., the varied tits tended to form small flocks in autumn and winter, although in the winter of 1974 all birds in the study area were found in pairs. 2) In both areas the same individuals of a pair normally remained together throughout the year, and from one year to the next, unless the mate died. On Miyake I., the individuals that were paired in the breeding season seem to have a closer relationship to each other than to other members of the small winter flocks. 3) The home range of each pair was nearly the same throughout the year, and from year to year in the pairs on the Izu Peninsula, although in the breeding season some pairs extended their home range to include areas where nest boxes were erected. On Miyake I., the home range and territory in the breeding season was usually established in or near the winter home range. Likewise, the home range was nearly the same from year to year. 4) Territory boundaries were relatively clearly defined for all the pairs on Miyake I., but were not always as clear in the pairs on the Izu Peninsula.