The nesting, roosting, and feeding trees of Black Woodpeckers (Dryocopus martius) were investigated in natural mature beech forests for clarifying the current geographical distribution of Black Woodpeckers at Aomori, Akita, and Iwate Prefectures in the northern Tohoku District, Japan. Home range sizes of the Black Woodpecker investigated were determined based on the distribution of field signs (new and old nesting, roosting, and feeding trees) in beech forests on Mt. Moriyoshi, and Mt. Oppu of the Shirakami area, especially during the breeding seasons. The area of natural beech forests in the study areas of the above mentioned three prefectures occupied about 370, 600ha. A home range size (HRS) was about 1, 000ha. Distribution range (DR) was about 64, 000ha in size, and the available range (AR) for the woodpecker was about 23, 000ha. By dividing the areas of DR and AR by HRS, the population size of Black Woodpecker was estimated to be 174 birds in the northern Tohoku District.
For at least 250 years, the harvesting of Streaked Shearwaters on Mikura Island was regulated by a series of traditionally developed and adopted rules based on ecological knowledge of the species that kept numbers at a steady level. The island's breeding population of streaked shearwaters it still one of the largest known in the north western Pacific. The traditional rules for harvesting were as follows: 1) only older chicks were allowed to be taken, 2) fowling was open on only a few days a year, and 3) only minimal disturbance of colonies was permitted during the breeding season. Chicks were taken for non-commercial uses at home and exchange with neighboring islands. Almost all parts of the chick bodies were used. The human population on Mikura Island was kept low due to the low carrying capacity of the island and the peculiar population control in the island society until the late 1800s, which also played an important role in avoiding over-exploitation of the shearwaters. Traditional taking of natural resources based on a good knowledge of ecology is quite different from the plundering of natural resources, which often occurred on other remote breeding islands of shearwaters and albatrosses caused by visitors without ecological knowledge.
Food consumption by penguins is an important component of energy flow in southern ocean food chain. We present a simple method for estimating daily food consumption of Adélie penguin Pygoscelis adeliae chicks by weighing them at regular intervals. Assuming that chick mass decrease rate is constant during food absorption period, their daily food consumption could be estimated by their initial mass and daily growth. Our method would be useful for estimating food consumption of individual chicks handled for other purposes with little additional disturbance.
Atresia and its changes during the annual ovarian cycle were studied histologically and histochemically (sudanophilic lipids and 3β-HSDH) in the ovary of the Indian yellow-throated wild sparrow (Petronia xanthocollis Burton). Study of atresia from serial sections of the ovary revealed that there were basically two types of atresia: non-bursting (lipoidal and cystic) and bursting (Types I, II and III). Non-bursting atresia was observed mostly in the primordial follicles, and bursting type exclusively in the larger follicles. Sudanophilic lipid was abundant in the lipoidal atresia but negligible in the cystic type. In the bursting atresia, lipid was negligible in early stage especially in the thecal glands but abundant in later stages. 3β-HSDH activity was absent in the non-bursting atresia, but present in the bursting atresia (early stage). Annual study of atresia showed that the non-bursting atresia was common and its frequency was higher than the bursting atresia throughout the year. The frequency of both non-bursting and bursting atresia increased during the progressive phase, became maximum in breeding and decreased during regression and non-breeding phases of the annual ovarian cycle. Lipid was maximum in breeding and regression phase, but 3β-HSDH activity was highest only during breeding compared to other phases of the reproductive cycle.
Super normal clutches were observed in the Black-tailed Gull Larus crassirostris at the colony on Kabu Island. I regarded clutches of 1-3 eggs as normal and those of 4 or 5 eggs as super normal. The super normal clutches were found in 31 nests (0.8% of 4, 034 nests examined): 5 in 1990, 5 in 1991, and 21 in 1992. Female-female pairings were reported for several species of genus Larus in USA as a cause of super normal clutches. Pairings of this type were not observed in Black-tailed Gulls, but instead, super normal clutches coincided with irregular sequences of egg-laying which suggested intraspecific nest parasitism.