The breeding ecology of five sympatric species of woodpeckers (Dendrocopos kizuki, Dendrocopos major, Dendrocopos leucotos, Picus canus, and Dryocopus martius) was studied from 1974 to 1976 in the broad-leaved forest of the Tomakomai Experiment Forest of Hokkaido University.
(1) In the Experiment Forest all of the five species of woodpeckers showed preference for the broad-leaved forest than for the coniferous plantation. All nest trees found were in broadleaved and second-growth forests.
(2) Among the five species, the breeding of White-backed Woodpeckers (D. leucotos) was earliest and their nestlings fledged in early June. The breeding of Black Woodpeckers (D. martius) was next and their nestlings fledged about the middle of June. Lastly, nestlings of Japanese Pygmy (D. kizuki), Great Spotted (D. major), and Grey-headed Green (P. canus) woodpeckers fledged in late June, about one month later than that of D. leucotos.
(3) All of the nests found were in broad-leaved trees. The nests of D. leucotos were relatively and absolutely higher than those of the other species. Seven out of 11 nests (63.6 %) of D. leucotos were found above the tree crown layer, whereas the nests of the other species were normally belowthat layer.
(4) In D. kizuki and D. major the main food of nestlings was lepidopterous larvae taken from the surface of leaves by gleaning. The food of nestlings of D. leucotos consisted mainly of coleopterous larvae taken from fallen logs and stumps by hammering and pecking. P. canus fed the nestlings with lepidopterous larvae and ants, whereas D. martius raised the nestlings chiefly with ants.
(5) The biomass of lepidopterous larvae reached to a peak from early to mid June at Tomakomai. The nestling periods of D. kizuki, D. major, and P. canus, which mainly depend on lepidopterous larvae to raise their nestlings, coincided with the peak of the biomass.
(6) The early breeding of D. leucotos was discussed from the points of view that breeding seasons in birds are timed in relation to the availability of food for their nestlings. It is suggested that the larger body size of D. leucotos caused the early breeding which was related to the effective utilization of coleopterous larvae. Further, some behavioral modification of D. leucotos associated with their early breeding were noted.

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Mt. Kisokoma (2, 956m above sea level) is the highest peak of the Chuo Alps, Central Honshu.Bird censuses were made throughout a year from February 1977 to February 1978 in the mid-mountain zone at 900-1, 650m altitude. Line transect method along the road is used in the census work. The total number of birds recorded was 1, 525 individuals belonging to 43 species (Table 1). The number of species and that of birds showed similar seasonal changes, i.e., maximum in the breeding season and minimum in winter. The dominant species were Pale-legged Willow Warbler Phylloscopus tenellipes, Siberian Meadow Bunting Emberiza cioides, Bush Warbler Cettia diphone, and Blue-and white Flycatcher Cyanoptila cyanomelana in breeding season and Long-tailed Tit Aegithalos caudatus, Willow Tit Parus montanus, Coal Tit Parus ater, Great Tit Parus major, and Nuthatch Sitta europaea in non-breeding season. A marked expansion of range in vertical distribution was noted for Siberian Blue Robin Erithacus cyane, Bush Warbler Cettia diphone and Blue-and-White Flycatcher Cyanoptila cyanomelana. Mixed flocks of tits were encountered in every censuses except for the three breedingmonths, and all five species of tits formed mixed flocks.

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The breeding distribution of Tree Sparrow Passer montanus in Hakone mountain region, central Honshu, was investigated from late April to the end of July in 1978. The study area (132.6 km²) is sectioned into 125 squares, each about 1 km² (30″ latitude × 45″ longitude) in area. Every square is investigated at least once by fifteen-minute random walk. The total number of observations was 185, in addition to 132 records for breeding checks in 62 squares.
Sixty-two out of 125 squares (49.6%) were inhabited by sparrows. They fall into four categories of breeding condition as follows :
Confirmed breeding (Grade a) 40 squares (64.5%)
Probable breeding (Grade b) 8 squares (12.9%)
Possible breeding (Grade c) 7 squares (11.3%)
Presence was recorded but no indications of breeding (Grade d)
7 squares (11.3%)
Since the breeding distribution of tree sparrows coincides closely with the distribution of houses and buildings, it seemed probable that the presence or absence of houses determines their breeding distribution. However, more careful analysis indicates that the breeding distribution of sparrows is correlated with human habitation rather than with the mere presence of houses.

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[in Japanese]

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