Alan Owston is one of the most famous naturalists of the Meiji Period in Japan. His contribution to natural history knowledge was briefly introduced in previous literature, however, no detailed biographic and bibliographic information was made available. This review compiles his achievements within both industrial and natural history contexts, drawing upon information obtained from academic publications, reports of research organizations and public newspaper articles. It pays especial attention to his friendships with contemporary specialists in several fields around the world, and also his employees, including specimen collectors of his company ‘Alan Owston’ at Yokohama. The author hopes this review will provide a basic data set of his life as a background to understanding the development of Japanese technological and biological research during the Meiji Period.
By improving the Band model (Band et al. 2007), Yui and Shimada (2013) developed a sphere shape model to estimate the number of bird-wind turbine collisions. However, given that the density distribution of birds flying through a proposed wind farm site is not uniform, a new method was developed whereby a proposed wind farm site is divided into blocks by the block count method to estimate the number of collisions in each block. First, the mean flight distances of birds passing through square blocks and circular blocks are calculated theoretically. Then, the calculated results are multiplied by the frequency of each bird species passing through the blocks in a certain period of time, which produces their total flight distances in each block. Once the total flight distances are obtained, the sphere shape model can be applied to estimate the number of bird-wind turbine collisions in each block for each bird species. Spherical models are based on the assumption that birds fly in a straight line in a wind turbine collision risk zone. We here show that spherical models and the block count method can be applied to both circling flight paths and curved flight paths. The number of collisions for circling and curved flight paths is close to the straight flight cases in every flight radius, except those under about 20 m radius, at which collision numbers of the smaller raptors become 1.3 times larger than that of straight flight paths. If the flight speed of birds decreases during the circling flight, the number of collisions rises in inverse proportion to the flight speed.
We have monitored the status of Black-tailed Gulls Larus crassirostris breeding on Tobishima Island since 2004. On Yurijima Islet, we estimated 2,034 nests in 1 June 2014 and observed a single cat Felis catus in the breeding colony and the carcasses of 14 adult Black-tailed gulls that probably were killed by a cat. We also found feathers of adult Black-tailed Gulls in a single cat feces collected on the mainland of Tobishima. Approximately 1,500 nests were estimated on Tateiwa Islet in 2009, but no nests were found in May 2014. To conserve the breeding sites of Black-tailed Gulls at Tobishima, immediate control management of the feral cat population is essential.
Seabirds capture squid in many ways, that mainly involve diving to capture them at the ocean surface or underwater. We present here the first photographic evidence of a seabird, a Red-footed Booby Sula sula, capturing an airborne squid. When a school of squid took flight following disturbance by our boat, a booby flying alongside swooped and approached a flying squid from behind, caught it in the air and ascended quickly. Soon after swallowing the squid, the booby made a plunge-dive and caught another squid that had just landed in the water after a period in flight. Plunge-diving was subsequently repeated over a separate school of squid that had just re-entered the water after flight. Seabirds other than the Red-footed Booby may have frequent opportunities for finding and feeding on airborne squid.
We monitored the breeding performance of Black-tailed Gulls Larus crassirostris on Kabushima Island from 2012 to 2015. During this period mean clutch size and productivity ranged from 1.57 to 2.14, and 0.03 to 0.29, respectively. The mean clutch size in 2014 and 2015 was higher than in 2012 and 2013, but the productivity in 2014 and 2015 was lower than in 2012 and 2013.
From 2012–2015 we conducted a Monitoring Avian Productivity and Survivorship (MAPS) program in Fukushima, Japan, using constant-effort mist netting and banding. Analysis of preliminary results, including adult abundance index, productivity index, and estimated adult survival rate, from four years of data showed no trend of increase or decrease. Continuous research for five to ten or more consecutive years is necessary in order to obtain reliable trends of productivity indices and estimated survival rates. Our results suggest that it is important to consider anthropogenic disturbances when study sites are chosen. To more-accurately analyze bird populations and dynamic parameters it is necessary to revise the JP MAPS protocol to include data from more study sites.
In 2015, a nest of the Okinawa Rail Gallirallus okinawae was observed using a video camera between 7 : 00 and around 12 : 00 from 1 June to 4 June, which was the day before all chicks hatched. The parents spent 95%, 93%, 94% and 83% of observation time incubating eggs on each day, respectively. The closer to the hatching day, the higher was the frequency of egg turning. Parents were present at the nest after 10 : 00 on all observation days.