The present study examined a possible determination of age in the Short-tailed Shearwater Puffinus tenuirostris by microscopic observation of sliced sections of the lower mandible. The section samples obtained from 14 individuals, aged from about one month-old to five or more years old, were prepared by decalcifying then staining with Delafield's haematoxylin. Results indicated that morphological changes in the mandible tissue were useful for the age determination of individuals during the growing period from one to six months-old, within nestling to fledgling. It was also found that morphological differences in the layered structure of the mandible were of use in distinguishing between sub-adults and adults. However, the number of layered structures was not consistent with the age of adult individuals.
We studied breeding ecology of the Grey-headed Lapwing Vanellus cinereus by tracing nesting of 31 banded adults and their precocial chicks in Ogura-ike Farmland, Kyoto, for five breeding seasons from 2007 to 2011. From incubation to chick-rearing periods, banded males and females of seven pairs took care of their offspring cooperatively and the monogamous mating system of this species was confirmed. The pair relationship was maintained over years, notably in two pairs which remained stable for four and five years, respectively, even after failure in breeding. Thirteen birds (four males, eight females, one bird sex-unknown) returned to the study area and nested on the same block of the paddy field. Thus, nest site fidelity in this species can be strong.
A specimen of Stejneger's petrel Pterodroma longirostris was collected in Okayama Prefecture, Japan, on 16 September, 2000. This is the first record of this species from the Seto Inland Sea. The specimen was identified based on morphology and DNA barcoding. As with all previous records of this species in Japan, we suggest this species as being a passage visitor.
The Grey-headed Woodpecker Picus canus was censused along 1,071 2-km transects situated in 953 5-km quadrats, in Hokkaido from late April to late July 1976–2014. Based on census results and records from the literature, Grey-headed Woodpeckers were recorded almost throughout Hokkaido, except on the plains and on neighboring islands. They occurred in 27% of quadrats in which censuses or observations were conducted, being observed mainly in mixed and deciduous broad-leaved forests, with occurrence rates (No. of transects of occurrence/No. of transects censused) of 22% and 23%, respectively, and at less than 550 m altitude.
From April to June 1993, Large-billed Crow Corvus macrorhynchos eggs at Ueno Zoological Gardens and Ueno Park were measured. During the breeding season, 68 eggs from 18 of the 43 incubated nests were measured. The range and mean dimensions of the 68 eggs measured were 39.4–54.7 mm, 45.2±2.8 mm (mean±SD) in length and 28.4–33.1 mm, 30.5±0.9 mm in breadth. The 67 eggs weighed ranged from 16.6–25.4 g, with a mean of 21.7±1.7 g SD.
We investigated the structure and materials of two nests of the Common Crossbill Loxia curvirostra collected in Shimokita Peninsula, Aomori Prefecture, Japan. The nest bowl was constructed of pine twigs with bark, shredded bark, wood-chips, other twigs, chemical fiber yarns, staple fibers, grasses, pine needles, feathers, rhizomorphs, animal hairs and fishing line. These materials were utilized in different manner in the exterior and interior nest bowl. Pine twigs with bark were used only for the most exterior portion, whereas the middle and interior parts consisted mainly of shredded bark of Cryptomeria japonica. Harder objects, such as twigs, wood chips and flexible fishing line, used for the middle part, served as a framework to produce a space between fibers and strings, creating a spongy layer of air. The area around the interior nest bowl was composed of thinner bark strings than the middle and outer nest bowl. Chemical fiber yarn, feathers and animal hairs were also found around the interior bowl.