The Crested Ibis Nipponia nippon became extinct in the wild in Japan in 1981, but was reintroduced on Sado Island in 2008, where the population has reproduced successfully since 2012. A total of 157 ibises is estimated to reside on Sado Island. To facilitate monitoring of survival and mortality, all the released individuals were individually identified through different combinations of color rings, and a uniquely numbered ring. However, because they were overlooked or present in inaccessible nests, not all wild-hatched nestlings were ringed for identification. In addition, the detection rate of the marked individuals might decline with an increase in the population size owing to the limited monitoring effort. Ministry of the Environment (MOE) has determined the number of unmarked individuals by the maximum number of simultaneous observations, and the number of marked individuals has been counted by subtracting the number of individuals that have not been observed for six months. Under such circumstances, the population size could be underestimated. To address this shortcoming, we fitted a mark-resight logit-normal model for estimating unmarked individuals, and a poisson-log model with robust design for estimating total population size including marked individuals, using program MARK. We also compared estimated numbers with observed ones. There were 8.48 unmarked individuals since the first successful reproduction in 2012. The estimated number reached a peak of 30.23 in 2014, but has gradually decreased to 20.30. In all study periods, the estimated number of unmarked individuals was larger than observed ones. However, the estimated number of marked individuals was almost the same as the observed one, but the numbers published by MOE were overestimations. At the end of September 2015, there were approximately 109 released and 41 wild-hatched individuals on Sado Island. When evaluating the reintroduction program, we recommend that the population size of the Crested Ibis should be estimated using mark-resight models. The result of this study will also contribute towards increasing accuracy in population estimates in other reintroduction programs.
A white Adélie Penguin Pygoscelis adeliae was sighted in offshore waters of East Antarctica at 65°56′S, 80°39′E on 20 February 2013. This individual had the same morphological characteristics and body size of normal Adélie Penguins, but had entirely white plumage, eyes paler than normal, a brownish to purplish red bill, pale pink legs and feet, and an absence of black coloration on the body. This individual was classified as a possible ‘ino-light’ according the color aberration types defined by van Grouw (2013).
A vagrant Cinereous Vulture Aegypius monachus was observed in the Kitakami Mountains, Iwate, Northern Honshu, Japan, on December 2, 2015. This is the first record of this species in Iwate Prefecture. During a three-month period after the original observation, the vulture was observed alone six times, at five locations in the Kitakami Mountains up to 50 km apart. At least two of six vultures observed were inferred to be the same juvenile individual.
We monitored the breeding performance of Black-tailed Gulls Larus crassirostris on Kabushima Island from 2012 to 2016. During this period mean clutch sizes and productivity ranged from 1.57 to 2.16, and 0.03 to 0.29, respectively. The mean clutch size from 2014 to 2016 was higher than in 2012 and 2013, but the productivity from 2014 and 2016 was lower than in 2012 and 2013.
A decrease in wintering sites in other countries caused by global climate change and other factors is one of several theories proposed to explain the increase in the number of large waterbirds wintering in Japan. As such, any increase in the number of geese wintering in Japan would not necessarily provide an optimistic view of recovery of population size, making it important to pay continuously monitor fluctuations in the number of wintering geese. Since 2002, we have counted the wintering Bean Goose Anser fabalis middendorffii in Edosaki-Iri Reclaimed Land, the only wintering site of this species in Kanto District, Japan. During the 14-year study period, the first individual arrived at the study site from mid-October to mid-November, and thereafter the number of individuals gradually reached a plateau within 13–46 days. Geese remained at the wintering site an average of 126.2±14.6 SD days (n=14), and the average maximum number of geese present during the plateau phase was 79.5±26.4 SD (n=14). Over the study period, geese usually began departing the wintering site in late February, and in most years geese departed the wintering site over a much shorter period that in which they arrived. In all years, all birds had left by late March. Arrival and departure dates remained relatively constant throughout the 14-year study, as did the wintering period. However, the maximum number of wintering individuals increased as the study progressed.
Dr. Yoshimaro Yamashina (1900–1989) was a Japanese ornithologist and the founder of the Yamashina Institute for Ornithology. His two-volume “A Natural History of Japanese Birds,” published in 1934 and 1941, was an important contribution that greatly influenced the development of Japanese ornithology. We have previously published “The Cataloging and Preservation of Manuscripts, Prints, and Related Materials Used for ‘A Natural History of Japanese Birds’” (Tsurumi et al. 2014). However, in 2016, additional materials relating to these volumes were found in the Yamashina Institute for Ornithology and at Dr. Yamashina's former residence. These additional 294 items were registered to the Institute's collection, and consisted of 116 original drawings, 157 trial prints and one picture, eight manuscripts, and 12 miscellaneous items such as errata slips and envelopes, increasing the entire collection to 821 items.
In 2016 we continued the Monitoring Avian Productivity and Survivorship (MAPS) Program in Fukushima, Japan, using constant-effort mist netting and banding. Preliminary analysis of results, including adult abundance index, productivity index, and estimated adult survival rate, from five years of data showed (a) the Japanese Bush Warbler Cettia diphone to have increased in Fukushima City and Minami-Soma City while decreasing rapidly in Iitate Village; (b) the Oriental Reed Warbler Acrocephalus orientalis to have increased in Minami-Soma City and to have decreased in Fukushima City; and (c) the Oriental Greenfinch Chloris sinica to have increased rapidly in Minami-Soma City. A simplified technique for recording habitat characteristics is required to assess the effect of natural disturbance and/or unexpected anthropogenic disturbances on bird populations and dynamic parameters.