A study of Paridae community in Japan

Abstract

1. Censuses of Japanese tits were made intensively at Tenryu River basin ca. 500m of altitude (102 times, 1957-'60) and Keito Mt. region below 1000m (95 times, 1963-'65), in Nagano Prefecture, Central Honshu. Supplemental censuses were made at: lowland Hokkaido (Sarobetsu, Kawayu, Gojukkoku and Onuma), subalpine Central Honshu (Kamikochi, Shiga), Shikoku (Kurokawa), Kyushu (Mt. Hiko, Ishiwara) and Tsushima (four places). These places had different vegetational environment and species composition of tits, but they were absent in pure evergreen broadleaved woods of southern Japan.2. The species of tits studied are: Aegithalos caudatus (Aegithalinae), Parus major, P. ater, P. varies, P. montanus and P. palustris (Parinae).3. At peripheral parts (Tenryu, Kurokawa, Ishiwara) of Paridae habitat of simple woods around human habitation, P. major and Ae. caudatus were main species; and only the former was found at the extreme periphery. P. varius joined them if there was a good amount of broad-leaved desiduous woods; P. ater occurred as a main member only during winter in Central Honshu where there was a mixed forest (Keito region); the main members were replaced in summer by P. ater and P. montanus at wet subalpine mixed forest (Kamikochi, Shiga); while in swampy lowland broadleaved forests of Hokkaido (Kawayu, Onuma, Gojukkoku), Ae. caudatus, P. major and P. palustris formed the main members, the last species becoming dominant in the more swampy part. P. varius and P. montanus occurred always in small numbers, but they may be more plentiful (dominate the others) elsewhere where they are best adapted respectively.4. The following three types of sympatry and ecological segregation among tits could be concluded:a. Two main species may coexist in similar abundance, but their types of social population fluctuation is different: Ae. caudatus concentrates into a compound family flock after breeding, while in P. major families are become dispersed. Thus, the two abundant species can coexist at peripheral areas.b. Two species may coexist in similar numbers and show parallel seasonal fluctuations, but the degree of fluctuation is different: Fluctuations of P. major and P. ater at Keito area were parallel but the wintering population of the latter species greatly increased, becoming very scarce in breeding season.c. One of the coexisting two species may dominate the other in number: P. montanus and P. varius in studied areas were decidedly few in number, although they coexisted with P. major and fluctuated parallel with it.5. Ae. caudatus is different from Parus species in the type of social population fluctuation and thus can be sympatric at such a peripheral part where P. major is abundant. Other Parus species may be similar in social fluctuation type, but coexist with each other by their different degrees of abundance in species composition due to different habitat preference or particular seasonal movement. P. montanus and P. varius, for example, are entirely allopatric in habitat, while P. ater is partly and seasonally sympatric with P. major and others.