(1) Asynchronous hatching, growth and survival of chicks in the Cattle Egret Bubulcus ibis were studied at a heronry in central Japan in 1978 and 1982.
(2) The average clutch size was 4.34 in 35 marked nests (studied only in 1978). Eggs were laid in the early morning at an interval of two days (70.3%) or more, averaging 2.27 days.
(3) Incubation behavior by both sexes started gradually a few days before first egg-laying. The average hatching interval was 1.88 days in 1978 and 1.93 in 1982.
(4) Both laying and hatching intervals tended to be prolonged in the latter half of the laying and hatching periods, respectively.
(5) The average hatching spread (data combined from the two years) was 6.3 days (N=72) with a maximum of 16 days (three instances).
(6) The first and intermediate chicks grew equally irrespective of their own brood size. Growth rates of the youngest chicks in B/4 and B/5 in 1978, as well as in B/3 and B/4 in 1982, were lower than older siblings.
(7) More deaths were recorded amongst d- and e-chicks in B/4 and B/5 than amongst a-, b- and c-chicks. It was likely that the former died of starvation or siblicide, whereas the latter died of various accidents.

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Roosting behaviour of the Little Egret Egretta garzetta and other egret species was investigated at seven communal roosts in Shiga, Osaka, Nara and Okayama Prefectures, Japan, between October 1975 and September 1983.
(1) Little Egrets gather in pre-roosting assemblies, but only in the non-breeding season.
(2) There were three types of pre-roosting assembly.
Type A: Egrets gather at certain pre-roosting site distant from the roost.
Type B: Egrets land on part of the roost forest.
Type C: Egrets swarm in the sky above the roosting forest before landing.
(3) Of the pre-roosting assemblies that I have found, 71.4% (N=7) were type A; this typeappears to be original type. If there was no site for type A assembly, egrets may gather intype B assembly. It is suggested that they gather in type C assembly when some disturbance (e.g.presence of predators) occurred immediately before gathering in type B assembly. Another causefor type C assembly is that in warm days egrets remain at the feeding site much later in the evening, arriving at the roost as a flock and forming the type C assembly in the sky above the roost.
(4) At a given roost, one type of pre-roosting assembly was usually found, although the pre-roosting assembly type changed from one to another.
(5) In the cases of type B and C assemblies, egrets always roosted near the assembly point.However, in type A assembly egrets occasionally used two assembly sites or two roosts.
(6) Behaviours observed during type A assembly were resting, feeding, and bathing. Thoughegrets spent most time for resting on the tree canopy in type B assembly, they occasionally repeatedflying up and down in the latter period of this assembly. Egrets gathering at type C assemblyswarmed over the roosting forest.
(7) Egrets chose a site less accessible to terrestrial predators (including man) as a pre-roostingsite. Frequent change of individual location was observed within a roost. Egrets seem to choosea location, avoiding cold stress.
(8) Assemblies at feeding sites and en route to the roost were not observed in Little Egrets.Only assemblies observed in this species were pre-roosting ones. The Distance between a pre-roost-ing site and a roost varied from 5 m (type B) to 5.5 km (type A).
(9) Roosting lacking pre-roosting assembly (direct roosting) was observed before and after theegrets gathering at the type A assembly moved to the roost; direct roosting was observed only afteregrests moved to the roost in type B and C assemblies.
(10) Quantitative data were obtained on the pre-roosting assemblies of types B and C.
i) Of all roosting birds, 70.6% gathered in pre-roosting assemblies.
ii) Mean time spent for pre-roosting assembly was 128.0 min; this is 82.1 % of the time betweenthe start of gathering at a pre-roosting site and the termination of roosting behaviour.
iii) Mean number of arrivals to the pre-roosting site was 150.4; 54.3% of all arrivals were ofsingle individuals.
iv) Movement from the pre-roosting site to the roost was made by 4.5 flocks and for 5.1 min, on average, respectively.
v) Mean time spent for roosting was 26.5 min.

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The number of thoracic vertebrae and the presence of the notarium were examined with the naked eye for 353 bleached skeletal specimens of birds belonging to 18 orders, 42 families, 105 genera and 147 species and subspecies. The results are as follows.
(1) The number of thoracic vertebrae of the skeletons examined varied from 6 to 12. Interspecific variations of the numbers of thoracic vertebrae were observed in Nycticorax nycticorax nycticorax, Melopsittacus undulatus etc. Anatid birds exhibited a very large coefficient of variation in the number of thoracic vertebrae, i.e. 14.0%. These results suggest that the number of thoracic vertebrae would be of little value as a differential character for species and genera of birds.
(2) The notarium has been observed in 103 species and subspecies of birds.
(3) The birds examined exhibited a great variation in the presence of the notarium, as well as the number and positions of thoracic vertebrae constituting the notarium. They also showed a variation in the number of thoracic vertebrae joining in the synsacrum.
(4) The notarium was observed in both terrestrial species (e.g. Phasianus) and arboreal species with a high flying power (e.g. Columbidae, Falconidae). It also occurs in the Fruidae and Phoenicop teridae, which are good flyers. Therefore it is suggested that the presence of the notarium may not be related to flyight style.

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A nest of the Short-tailed Bush Warbler Cettia squameiceps was found in the Japanese Cypress Chamaecyparis obtusa forest, at Owachi (E 137°57′, N 53°28′, altitude 700 m) in Shimoina-gun, Nagano Prefecture, on 29 April, 1981. On 30 May, one of the authors noticed 3 adult birds attending the nest simultaneously. In order to compare differences in nestling-care behavior of these 3 birds, a continual nest-watch was carried out for a total of 228 min. on 31 May. Two birds are considered to be the parents and the other a helper. This is the first observation of helping at a nest of the Short-tailed Bush Warbler in Japan.

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An adult male Ring-necked Duck Aythya collaris was observed at Shinobazu Pond, Tokyo, from February 29 through April 9, 1984. It was seen with flocks of Pochards Aythya ferina and Tufted Ducks A. fuligula. This is the second record of Ring-necked Duck in Japan.

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[in Japanese]

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