Breeding ecology of the Short-tailed Bush Warbler Cettia squarneiceps was investigated in western Hokkaido during five seasons (1990-1994). The first arrival and first egg-laying dates were similar among years. Clutch sizes varied between 4-6 eggs, but they decreased as the breeding season progressed. The mean incubation and nestling period was 12.9±0.5 days (SD, n=18) and 10.0±0.4 days (SD, n=17), respectively. Only females incubated eggs and brooded nestlings for a long period of time. Most of the feeding of the young was conducted by males. Different (beta or gamma) males from the resident (alpha) male appeared and sometimes fed the young in 48.1% of twenty five nests observed. Some males were captured at locations far from their own nests, while there were only few cases in which a female was captured at a place distant from her mate's song area. As it was often observed that a beta male was the neighboring territory holder and his own nest was in the incubation period, it is hypothesized that some males who are emancipated from the incubation, might visit other territories to seek extra-pair copulations (EPC). We have, however, not observed mating between a female and a beta male except in the case of a widow. Within the breeding season, the females usually selected the same partner for the second brood. Main reason why the divorce rate within the season is low for the warbler in our study area is probably the high success rate for the first brood.

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Skull pneumatization was examined in relation to actual age for 37 known-age Hazel Grouse Bonasa bonasia raised in an aviary. Although pneumatization advanced with increasing age, unpneumatized areas (UPA) were present on the cranial roof even in old adult birds. Five indices indicating the size of UPA, i. e. 1) length of UPA, 2) width of UPA, 3) length of UPA × width of UPA, 4) length of UPA/total length of skull, and 5) width of UPA/greatest width of skull, were examined. Of the five indices, the fifth index was a reliable criterion for separating first-year birds of 4-8 months of age from older birds of_??_15 months of age; the index value was 0.158 to 0.306 for the former and 0.063 to 0.145 for the latter. The value for separation is 0.15. This criterion was adopted to determine the age of Hazel Grouse killed during hunting seasons from 1 October to 31 January in Hokkaido, Japan. Of 49 birds examined, first-year and older birds accounted for 77 and 23% respectively.

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Relationships are examined between laying dates of aerial insectivore Little Swifts Apus affinis and weather conditions during the pre-laying periods from 1986 to 1989 at a colony in central Japan. The breeding season was remarkably long, with first eggs laid in mid-April and last chicks fledged in ealry December. Almost all pairs annually fledged two or more broods. Mean laying dates for first clutches varied significantly among years. Temperatures during about one month before laying were important to mean laying dates of first clutches. Mean laying dates for both second and third clutches also varied significantly between years. However the mean laying dates had no significant relationship to weather conditions before laying. It is likely that the correlation between egg laying for successive clutches led to the significant yearly differences of mean laying dates for second and third clutches. Female age also affected laying dates. Females of three years old or more (≥3-yr) highly significantly laid eggs earlier than two-years-old (2-yr) females for all the three clutches. The number of clutches that female produced annually varied significantly between years. Individual females that bred earlier had more clutches than those that bred later. Females of ≥3-yr had more clutches than 2-yr females, because ≥3-yr females laid eggs earlier than 2-yr females.

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[in Japanese]

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[in Japanese]

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At least 11 final instar nymphs of the evening cicada Tanna japonensis were found in the crop of a dead Grey-faced Buzzard Butastur indicus collected from Ogane, Minaminasu-machi, Nasu-gun, Tochigi Prefecture on September 13, 1987. This is the first record of the predation on cicadid nymphs by B. indicus.

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Winter bird survey was conducted along the climbing path and the road along the coast of the Ullung Island, from 12 to 19 January, 1995. During the survey a total of 786 birds belonging to 16 species, 14 families, and 6 orders, were observed. Among them, dominant species were Black-tailed Gull Larus crassirostris (7.81/km, 41.4%), Great Tit Parus major dageletensis (4.13/km, 24.7%), Brown-eared Bulbul Hypsipetes amaurotis (2.17/km, 13.0%), Yellow-throated Bunting Emberiza elegans (1.62/km, 9.7%), and Tree Sparrow Passer montanus (1.60/km, 9.5%). Tree Sparrows were recorded in Hyonpo only. The occurrence of Tree Sparrows may be related with food supply and snow cover in winter on the Ullung Island. Russet Saprrow Passer rutilans reported as a resident in South Korea, was not found during the survey.

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A nest hole in which a female (grey phase) sat was found on 22 June 1994 at 1, 160m asl. of Mt. Takamaru, Tokushima Prefecture. Four eggs were seen in the hole on 28 June and three nestlings were observed on 18 July. In addition to these observations, a male (brown phase) singing on a branch near the nest hole was seen on 16 June.

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I observed Peregrine Falcons Falco peregrinus preying on House Swallows Hirundo rustica, which were going to roost at two sites, Tottori and Wakayama. In both cases, Peregrine Falcons preyed on a House Swallow flying in flocks over a reedy marsh after sunset. It is suggested that the Peregrine Falcon regularly preys on House Swallows at dusk from summer to autumn, if the House Swallows roost is located in the home range of the Peregrine Falcons.

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