In 1969, a pair of Jungle Crow Corvus macrorhynchos was kept under observation from later incubation period (April 13, five days before hatching) at Akasaka, Tokyo, where I lived in its breeding territory, which was about 45.83 ha, 1000m east to west (200m to west, 750m to east from nest) and 700m north to south (500m to north, 200m to south), thus oval in shape, with the nest situated near the round end. The northern (to the direction of winter roost) and eastern (toward summer roost) territorial boundaries are deliminated by big buildings of TBS television and Parliament respectively.
The territory contains apartments, buildings of various sizes, small shops and private houses, with wooded shrine of Sanno on the hill of north-east border, wooded lawn slope of Prime Minister's official residence at eastern hill, and on the central hill, two big gingko trees, one of which having crow's nest, stand high with a patch of trees. Thus, there are some greens on central and surrounding hills, between which two main roads, one with highway, run crossing at Tameike (Fig. 1).
Main buildings and other objects frequently used by crows, for resting, guarding, food storing and eating places, are numbered on territory map, with distance lines of 50m mesh (Fig. 3) and circles (Fig. 2).
Observations were made on the roof of my home about 40m apart from the nesting gingko tree and I could see all directions of surrounding hills, except some blind area at south western part.
Observation time, usually more than 2 hours for each observation, was selected according to its purpose of following the male's movements in its morning food search commenced as soon as he returns from flock roost to his territory before sunrise, female's attendance rate to nest and her daytime activity in relation to her mate or intruding other crows, feeding rates to chicks by male and female, food storing and hiding, roosting places, sexual and family life, as well as vocal communication.
In the present paper (part 1; to be continued), observation data from April 13 to 30 are given with some tables and figures.
1.The incbation is engaged by female only, but male may visits nest with 20-30 minutes intervals, calls her for confirmation or inviting for food, and if the male doesn't return long time from food search, the female may leave the nest in search of him, in some cases advertising herself by circling flight.
2. Although sitting on nest in the foliage, the female is very keen to outside event or for vocal communication of the male and as soon as she perceives, or notices by male's voice, other crows trespass flying over beyond territorial boundary, the female at once takes off from the nest directly flying, with attack calls, to the intruders to chase them up from below. The male is, however, usually less aggressive, or even indifferent, being occupied by his job of food search for the day (But, when he is less occupied he may lead the defense chase of intruders).
3. Finished the daytime activity of food search toward evening, the male rests on high top or antenna of building more or less 100m apart from the nest, and the female leaves the nest to pass some 15 minutes with the male preening or billing each other, and together return to nest site (to gingko tree adjacent to nesting gingko). Thus ended their activity of the day, the male leaves (with soft 'ka' of roosting signal vocal) to common flock roost about 1km from the nest site and the female gets back to the nest for her night incubation or brooding of early chicks (from 31st day after hatching the female also flew off to roost).
4. Before sunrise, the male comes back to his territory in the dark of twilight, which the female on nest at once notices by his approaching call notes, and answering to him she flies out to adjacent tree to wait his arrival.

View full abstract

This paper discusses the problems of ecological distribution in avian mixed population of closely related sympatric species as revealed in the Paridae community in Japan. Structure and distribution of home ranges of five species of tits (Aegithalidae and Paridae) are compared by analysing intra-and inter-specific relations in the ecological separation of social structure between species.
1. The vegetation of artificial mixed forests of study area in the mountain region about 1000m of altitude in central Japan, consisted of deciduous woods of Quercus serrata, Castanea crenata, Betula platyphylla and Alnus Japonica and coniferous plantations of Pinus densiflora and Larix leptolepis.
2. In these mixed forests, five tit species Aegithalos caudatus, Parus major, P. ater P. montanus and P. varius are sympatric and Ae. caudatus, P. major and P. ater maintain annually stable high population densities, P. montanus has low density and P. varius is represented by only one pair.
3. Social systems of Aegithalos and Parus are essentially different. That of Aegithalos is characterized by flock unit which is maintained by flock territoriality, consisting of 'flock range' and 'flock members'. During winter, the territoriality of flock unit is strengthened by 'group displays' and in the breeding season the means of maintenance of territoriality are shifted from 'flock unit'to 'pair unit'. In Parus, on the other hand, the base of social system is the 'pair unit', which is emphasized by singing activities and fighting behaviour and in winter the territoriality is weakened, with the result that the home range of pair unit is extended and the tendency of flocking together with adjacent pair unit is raised.
4. The pair unit in Parus is maintained through the winter, especially in milder weather. The tendency of pair unit is strongest in P. montanus, while P. major and P. ater show the tendency for flocking. However, although there are gradations of types in the species of Parus between flocking and pairing tendencies which are also subject to population densities, there esists no intermediate type between flock unit system of Aegithalos and that of pair unit in Parus. This is the essential difference of social systems of these two genera.
5. The patterns of ecological separation (or segregation) in the interspecific relations are different by winter and breeding seasons. In winter, the separation occurs in vertical layers of the forest and in breeding season it is horizontally mosaic, with distinct interspecific overlaps of home ranges, but main feeding areas are segregated. The pair unit supported by territoriality has important function in dividing same resources intraspecifically, but interspecifically the pair units are overlapped.
6. No case of interspecific territoriality is known among Parus species, although interspecific territorial overlaps are found in P. montanus-varius group and P. major-ater group along the marginal zones of habitat of each species. Wide overlaps of distribution among tit species are, in my opinion, the effect of mutual avoidance within a mixed flock, not being the process of the development of interspecific territoriality.
7. Parus species make mixed groups (or flocks) attracted by and attached to Aegithalos flock which is 'flock-unit' society, but Parus species society is basically 'pair-unit', although it makes flock by grouping of pair-units.

View full abstract

1. In October 1962-January 1963 and October 1963-January 1964, foraging behavior of tits and other species forming mixed flocks were observed at Botanical Barden of Tohoku University in Sendai, for the purpose of analysis of interspecific relations.
2. During winter season, the foraging differed by species in the following manners: the Longtailed Tit Aegithalos caudatus took food mainly from bark and foliage; the Great Tit Parus major from bark, foliage and ground; the Coal Tit P. ater from foliage, bark and cones; and the Goldcrest Regulus regulus from leaves of conifers (by hovering), foliage and bark.
3. Statistically, the percentage frequencies of foraging patterns differed by species significantly, with confidence intervals in 60% reliability (Kato 1955), showing that each species in mixed flocks takes food by its own specific foraging method.
4. The same statistical comparison, by confidence intervals in 60% reliability, was applied to the analysis of foraging patterns of each species in mono-specific (Sf) and mixed flocks, with (Mf+) or without (Mf-) Long-tailed Tit.
As the result, the Long-tailed and Great Tits showed no change in their specific foraging patterns in either kind of mixed flocks (Sf, Mf+ or Mf-). But, significant change occurred in the foraging patterns of Coal and Willow Tits, as well as Goldcrest, when they belonged to diffrent kind of mixed flock. These three species should therefore be affected by the presence of other species, especially through the interspecific "supplanting attacks."
5. Judging from the number of interspecific supplanting attacks and of approach-avoidance, the Great Tit is most aggressive among these flock forming species, the Coal Tit being the second, and Long-tailed Tit, Willow Tit, and Goldcrest are in lower ranks as for aggressiveness, but the order of aggressiveness among these three species are not clear.
6. It is suggested that the order of aggressiveness of each species forming mixed flocks is different from the leading order of foraging movements of mixed flocks.

View full abstract

1. During 1962-64, the life cycle of the Long-tailed Tit Aegithalos caudatus was studied in the Botanical Garden of Tohoku University, Sendai, 60-146m of altitude. This paper reports its nesting behavior, nest-site selection and territorial behavior.
2. Some pairs started nest-building as early as in late February, with peak of nesting in early March, and early nesters were slow nest-builders. Incubation began from early April, when the mean temperature gradually becomes higher than 10°C, and the nestling period was in May.
3. Of the 21 nests examined during 1962-64, only 7 nests, 34.3%, were successful and nest damage was highest in incubation period.
4. Out of 21 nests, 7 were built in spruce fir tree Abies firma, 5 in red pine Pinus densiflora, 4 in Cryptomeria Japonica, and thus, 16 nests out of 21 examined were built in coniferous and 5 in deciduous trees.
5. The nest site varied from high branches in tree canopy to 0.3m from the ground and were built in trees as tall as 30m down to undergrowth of less than 1m. All the nests built more than 10m from the ground were destroyed (by wind or predator) and successful nests were all at less than 10m in height.
6. Of the 21 nests examined, 18 including all successful nests, were found near the ridge of hill down the slope to about 80m.
7. Each pair had nest-material gathering and feeding ranges. The former kind of range was restricted to one slope side owing to the labor of carrying nest-material, and was average about 20000m² in area, while the feeding range covered more than one slope having average about 50000m² and average 2.55 times larger in area.
8. It was found that nests were rather evenly spaced 200-300m or more apart with each other, and chasing behavior was observed against adjacent pair or other birds such as jay or coal tit at peripheral or overlaping parts of the feeding range. These observations reflect territoriality of the Long-tailed Tit, although it lacks distinct territorial behavior.

View full abstract

1. Based on data of 56 censuses in July 1961-January 1962 and 124 censuses in April 1962-April 1963, and of other observations during 1960-'65, the annual number fluctuations of Long-tailed Tit Aegithalos caudatus in the Botanical Garden of Tohoku University, Sendai, are analysed.
2. As compared with territorial annual life cycle of Great Tit, the annual cycle of Long-tailed Tit is based on flock life with separate pair life in the breeding season, which is started in late December 11/2 month earlier than in the Great Tit.
3. The number of breeding Long-tailed Tit was same as the number in previous winter flock. One male bird banded among 16 birds in 1962, nested near its birth place in 1963 and '64. It was found in the same summer and autumn-winter flocks of 1962, '63 and '64.
4. Each bird in autumn-winter flock of Long-tailed Tit remains in the next spring in its winter flock (or feeding) range, the number of breeding birds in spring being about the same as that of winter flock. Thus, the home range and size of winter flocks are important in determining the breeding area and density in the next spring.

View full abstract

1. The Japanese Marsh Warbler Megalurus pryeri is a very localized endemic relic species, known from Aomori to Pacific side of Honshu. In 1973, it was first found in Akita at an small reed area remaining at an uncultivated corner of Hachirogata reclaimed land. Its breeding ecology was investigated by the author during June to September 1973 and 1974.
2. At present, the reclaimed farmland is about 2, 340ha and reed bed occupied about 62.6% of uncultivated area in 1973, decreasing to 11.7% in 1974.
3. This Marsh Warbler had apparently been concentrated in the western half of the reclaimed land of Hachirogata. Its male count was 29 birds in 1973, increasing to 53 birds in 1974. It is to be noted that both its distribution area and density has increased in 1974 (than in 1973) inspite of the decrease of reed bed area.
4. Within reed bed area, its favorite habitat is characterized by mixed undergrowth community of dead previous year reed, Mischanthus sinensis, Imperata cylindrica var. Koenigii and Scirpus triqueter, etc. The area of its highest density, where half of singing males were recorded, was about 80ha of uncultivated field at western part of the reclaimed land.
5. The breeding observation was made in the above concentration area. The total of nests observed was 6 in 1973 and 14 in 1974. The nests were found, 1) 55% in the reed Phragmatis communis, 2) 25% in stumb of Eulalia Mischanthus sinensis, 3) 20% in the undergrowth, and most of its nests were located at about 10.5cm above the ground.
6. The nest type could be classified into: 1) Typical bowl shape, constructed by placing nest material from the bottom (Type 1) 2) Elliptic shape, resembling the nest of bush warbler Cettia diphone 3) Globular shape made of fresh grass with dead grass base. The nest of any of these types was made coarsely and fragile.
Egg was laid one per day and clutch size was 5-6 eggs (av. 5.3 eggs), the egg size being av. 16.6×12.4mm.
8. Eggs were incubated by female only after completion of the clutch for average 11.3 days, with the hatching rate 98.1%.
9. Chicks were fed 76.8% by the female with regular intervals and 23.2% by the male with unstable frequency.
10. The feeding rate per 1 chick/hour was average 0.44 times/hour by the male and 1.54 times/hour by the female, with 1.98 times/hour by both parents. The nestling period was average 12.1 days.
11. Number of chick's feces was 49.7% of the total number of food given and the frequency the parents carried off chick's feces was about 50% of feeding frequency.
The main chick food items, in order of frequency, were adult moth of Pyralidae, lavae of crickets Conocephalus sp. and spiders. The Pyralid moth occupied about 14.3% of the total chick foods.

View full abstract

This paper, firstly, analyses the nesting records of Japanese bunting (Emberiza spodocephala), Japanese brown thrush (Turdus chrysolaus), Japanese bush warbler (Cettia diphone), Chinese tree pipit (Anthus hodgsoni), Bull-headed shrike (Lanius bucephalus), Japanese meadow bunting (Emberiza cioides) and Japanese grey thrush (Turdus cardis), based on the data collected by the author from 1966 to 1968 and other investigaters at the foot of Mt. Fuji, and, secondly, discusses the factors determining the seasonal and annual variations of clutch size.
1. In E. spobocephala, C. diphone, A. hodgsoni, L. bucephalus and E. cioides, the clutch size shows the tendency to decline in the course of the season, and in T. chrysolaus and T. cardis, it shows the mountain-shaped variation having the peak during second-half of June and first-half of July (Tables 1-12)
2. Second broods were recorded in E. spodocephala, T. chrysolaus and E. cioides.
3. As the cause of the seasonal variation in clutch size, it was considered, as already pointed out by Lack (1966), that it may be the result of adaptation in each species to the seasonal variation of specific food abundance for young birds (Tables 13, 14 and Fig. 1).
4. Generally speaking, the mean clutch size becomes larger in such years when the breeding started earlier on account of higher temperature in early spring. The author thinks as the cause of such a phenomenon, despite of Lack's paper (1966), that there may be more animal food for young in years when breeding started earlier, because the food resource will remain much more on account of reduction in predation rate on animal food by birds during warm winter.

View full abstract