Young (2 to 3 months old) and adult (more than 8 months old) Budgerigars (Melopsittacus undulatus) were purchased from a pet shop on April 5 and May 5, 1984, respectively. The daily water intake of both groups of budgerigars was observed for 13 to 14 months following the date of purchase and an examination was made of the dipsogenic action of angiotensin II (AII) on each group. 1. A peak in drinking activity was observed 1hr before and 1hr after the light was turned off at 2 weeks and 6 days following purchase in the young and adult specimens, respectively. However, after 4 to 5 months following purchase, two peaks in the drinking patterns could be observed in both groups: one soon after turning on the light and the other, 1hr before turning off the light. These drinking peaks were more prominent in the young than in the adult Budgerigars. They became less evident in June, 1985 in both groups. 2. No significant correlation was found between daily drinking patterns and changes in daily humidity. 3. The mean percentage of the number of birds drinking per hour in the daytime was 38.9 (young) and 14.3 (adults) at 2 weeks and 1.5 months following purchase, respectively, indicating that young Budgerigars drink once every 2 to 3hrs and adult once every 7hrs. Thereafter, the percentage increased beyond 50 in both groups, indicating that all the birds drink at relatively short intervals (about once every 2hrs). The percentage was always higher in the young groups, meaning that the young birds drank at shorter intervals. 4. The mean amount of daily water intake was 1 to 2ml/bird at 2 weeks and 1.5 months after purchase in young and adult birds, respectively, and increased gradually to 3 to 3.3ml/bird at about 7 months (November, 1984) and 10 months (March, 1985), respectively. This increased level continued up to June 11, 1985 in the young. In the adults, water intake decreased from March to about June, 1985. The mean amount of daily water intake was always greater in the young. 5. A significant correlation was found between the mean amount of daily water intake and mean daily humidity in both groups. 6. The percentage of water ingested in the day to the total daily amount was less than that drunk at night at 2 weeks and 1.5 months in the young and adult groups, respectively, but thereafter this tendency was reversed. In any one month, the percentage in the young always exceeded that in the adults. 7. Following a single intraperitoneal injection of 10μg/100g of AII, more than 50-100% of the young responded by drinking, but only 0-71.4% (usually 12-40%) of the adults did so. AII was more dipsogenic in the young than in the adult birds.
Density, speies richness and diversity of breeding bird communities in nineteen types of vegetation in Japanese woodland were estimated based on 190 censuses. Two types of density value were calculated. The first, relative density (n), which is the total number of individuals of all species recorded during a one hour line transect census made under standard conditions: viz, conducted around 150 minutes after sunrise, 50 meters observing radius, 1.5km walking speed per hour and in favourable weather. The second, is absolute density per 15 hectares (D), which was estimated from the regression formula of correlation between and the absolute density of study the areas. Two types of species richness value were also calculated. One, the number of species (S) recorded during a one hour line transect census made under standard conditions, was estimated using the correlation between actual S, in several study areas, and values gained by Rarefaction method (James & Wamer 1982). The other is the number of species (ST) which is considered to be actually dwelling in 15 hectares, and was estimated using correlations between actual ST and S in several study areas. Moreover, the maximum number of species (S'max) thought to be dwelling in each type of vegetation were estimated, and the number of species dwelling in different areas were estimated using the law of truncated negative binominal distribution. Two types of bird species diversity (BSD) value were calculated using the Shannon-Weaver function: viz. BSD=-PiΣlog2 Pi. One is rude BSD (H') which was calculated from rude census data in each vegetation type. The other is the estimated value of BSD (H') which will be thought to be attained during a one hour line transect census made under the standard conditions, and was calculated by J'•log2S, where J' is a mean of evenness derived from rude census data in each vegetation type. There was a positive correlation between D and ST. Also, D and H', showed a positive correlation with FLD (forest layers diversity), which is calculated by (4Σai_??_aj=1ai•aj)1/2, where ai and aj take relative values checked by foliage cover in four layers woodlot: viz, no cover O, sparse 1/3, medium 2/3, dense 3/3. BSD was considered to be determined primarily by FLD or FHD (foliage height diversity; Macarthur & MacArthur 1961) and the degree of the mixture of broad-leaved and needle-leaed trees in the crown layer. Moreover, it was thought that conditions of geographical or topographical loci and continuity or patchiness of vegetation would be important factors affecting BSD. Finally, methods for utilizing the data in this report, and for collecting or standardizing techniques of collecting data for the purposes of comparison, were suggested.
Adult male Blossomheaded Parakeets were held under artificial very long (22L) and very short (2L) daily pohoto periods either for 45 days or for both 45 days and 90 days during different phases of the annual gonadal cycle. These experiments were designed so as to establish: (i) whether this is at all photosensitive or not; and (ii) if photosensitive, the importance of the duration of the photoperiod in the periodic activation of the testes of the bird. Longer periods of artificial light or darkness did not affect spermatogenesis throughout the preparatory and early progressive phases (May through October) of the annual reproductive cycle. But the testes of the parakeets became precociously mature when the birds were held in long photoperiods, for 45 days, during the late progressive phase (Nov. -Jan.). The same photoperiodic regimen caused testicular involution when the treatment was extended up to 90 days. During the same reproductive phase retardation of testicular growth was attested with the studies of the birds kept in darkness for 45 days. Under identical photoschedule the occurrence of spermatogenesis was noted in a few tubules of the testes of birds held in darkness for 90 days. During the prebreeding phase (Jan. -Feb.) the testes of the long photoperiodic birds were spermatogenetically active after 45 days treatment, but regressed when the treatment was continued for 90 days. Long daily darkness periods for durations of 45 and 90 days during the same reproductive phase induced retardation of testicular growth. None of the used photoschedules, i. e. 22L 2D or 2L 22D, appeared to affect testicular regression, a time bound natural phenomenon of the free-living species, when the birds were treated for 45 days after the breeding phase (Feb. -March) of the annual gonadal cycle. The results indicate that: (i) the duration of daily Photoperiod probably has no important role in the seasonal recrudescence of spermatogenesis, but the same factor may have certain uses in promoting further spermatogenesis in the testes of the bird; (ii) influence of the prolonged duration of very long stimulatory photoperiod is inhibitory to the testicular functions of this species; (iii) artificial long or short days cannot affect the periodic testicular involution; (iv) this bird becomes photorefractory during, at least, the preparatory and early progressive phases (May- Oct.) of the annual gonadal cycle; (v) the duration of photorefractoriness is possibly not less than a period of six months. As a tentative unifying hypothesis to be tested, it may be suggested here that in case of the low-latitude male Blossomheaded Parakeets, the duration of the available photoperiod possibly constitutes part of the battery of information used in timing reproductive functions.
The male sex accessories were studied from gravimetry, histology and biochemical standpoint during the annual testicular cycle and nesting cycle in a sub-tropical passerine bird, the Pied Myna (Sturnus contra contra). The findings revealed that all the sex accessories showed cubodial to low columnar, non-ciliated and non-secretory cells, with low seminal glomus weight and sialic acid content during the non-breeding phase (August to January). The epithelial cells were moderately enlarged with a moderate increase in seminal glomus weight and sialic acid concentration during the pre-breeding phase (February and March); greatly enlarged with differentiation of cells and secretory activity followed by a further increase in weight and of sialic levels of the seminal glomus during the breeding phase (April and May); and regressed with reverse changes in the seminal glomus during the post-breeding phase (June and July). During the nesting cycle (i. e. the breeding phase) particularly the early nest-building period, the values of all the above parameters in the sex accessories increased. They were highest in the late nest-building period and decreased gradually in the egg-laying, incubation and nestling periods. It is suggested that in the Pied Myna, sex accessory activity varies simultaneously with the annual gonadal cycle, being low during the non-breeding phase, at a moderately increased in the pre-breeding phase, at a maximum during breeding and declining thereafter. But during the nesting cycle sex accessory activity increased in the early nest-building period, attained a peak in the late nest-building period and declined gradually in the egg-laying, incubation and nestling periods. Changes in the sex accessories are considered to be the result of changes in ovarian steroid activity during the gonadal cycle of this bird.
In 1985, a colony of streaked shearwaters (Calonectris leucomelas) with about 6, 600 burrows was surveyed in the Ohshimawake-gawa valley, on the north-eastern part of Mikura, an island in the Izu Island group off central Honshu, Japan. This colony, covering 3.4ha was located on a coastal cliff more than 300m high, and its burrow density was higher (over 0.5/sq.m) along the cliff edge than at areas away from the edge. Complication of the burrow structure by frequent use corresponded to the increase of burrow density. The degree of cover of shrubs and grasses decreased as the burrow density increased; more than 40% of the colony had less than 40% of the CD value. The cliff edge was the most frequently used site for take off, followed by inclined trees, 6-12m high, away from the edge. Few trees were used for take off on the lower slope near the valley bottom. Annually eliminated soils by burrowing were far greater in volume than natural soil formation from the materials, and the surface soil erosion in the colony was from several to some dozen mm per year, being several tens to hundreds times the volumes in natural areas with dense ground cover. The period of use of the colony was estimated to be 40-230 years using those erosion speed and the soil depth of 60±42(SD)cm(n=11).