We determined the habitat selection of Whooper Swan Cygnus cygnus, Northern Pintail Anas acuta and Mallard A. platyrhynchos wintering around Lake Izunuma-Uchinuma, northern Japan, by using Global Positioning System (GPS) tracking during the winters of 2015/16 and 2017/18. The GPS device, GPS-TX (Mathematical Assist Design Laboratory) is attached to the bird and transmits the location data to a base station so that the bird does not have to be recaptured to retrieve the data. Whooper Swans showed a diurnal foraging pattern and were located in open water where lotus was abundant, and at an artificial feeding area in Lake Izunuma-Uchinuma. A smaller number of observations were from paddy fields around the lake. Northern Pintails showed the characteristics of both diurnal and nocturnal activity patterns. Pintails in 2015/16 mainly stayed in the artificial feeding area during the day, and some of them moved to the paddy fields to the north and east of the lake at night. The distance from the lake to these paddy fields was an average of 2.5km. Pintails in 2017/18 remained in the artificial feeding area, and during the day they stayed close to the parking lot where people fed the ducks. Mallards showed a nocturnal activity pattern, as they moved to the paddy fields to the north of the lake at night. The distance from the lake to the paddy fields where Mallards stayed at night was an average of 4.5km. Of the farmland surrounding Lake Izunuma-Uchinuma, Whooper Swans and Northern Pintails selected to use dried paddy fields, but Mallards used flooded paddy fields. GPS-TX was shown to be a useful technology to track waterfowl, and hereafter is expected to shed light on wintering ecology
I surveyed the abundance of Great Bitterns Botaurus stellaris annually during the breeding season (late March to June) from 2008 to 2017 in Watarase Marsh, central Japan, and recorded the number of vocalizing (booming) males. The survey was conducted for three hours (two hours before and an hour after sunrise) along a 15 km long course through the three regulated reservoirs at Watarase Marsh. This study stands on the assumption that every booming individual is male, and that their booming indicates an indirect proof of their breeding in the study site. One to five males were recorded per day along the census course. A maximum number of four males was recorded in the first reservoir, which had the highest occurrence rate among the three reservoirs. The abundance of males, however, declined after 2013, after which only one or two males were recorded in the study course. Most of the locations where booming was recorded were less than two hectares in area, and the water depth was less than 20 cm. The highest occurrence rate was recorded in an artificial pond, covered with cattails Typha angustata, on a golf course. Although Watarase Marsh is a relatively large reedbed of about 1500ha dominated by common reed Phragmites australis and Japanese silver reed Miscanthus sacchariflorus, it is relatively dry with very few areas of reed swamp. It is suggested, therefore, that Watarase Marsh does not currently provide the preferred breeding habitat for the bittern. This situation could be improved, as evidenced by a booming male, recorded in the breeding seasons of 2016 and in 2017, which was located on a new pond with reedbed created by a wetland restoration project. Creation of a new reed swamp, by a wetland restoration project implemented at the second regulated reservoir, is considered to be an important for expanding the suitable breeding habitat of this species.
Daurian Redstarts Phoenicurus auroreus have been known only as a winter visitor in Japan, but in June 2010 breeding was confirmed in the town of Fujimi, Nagano Prefecture. As a result of our continued survey for eight years thereafter, 64 breeding events were confirmed in the vicinity of Yatsugatake. Between 2010 and 2017 the number of breeding events increased, and this suggests that a breeding population has been established. We identified several environmental characteristics of nesting sites, including an apparent preference for villas/resorts instead of for woodlands, with a preference for structures regularly occupied by people. Artificial objects, such as hoods for ventilation fans, were often used as nest sites, with typical nest height of about 2 m above ground level. In those residential areas, the nest sites were close to the edge of the woodlands. These observations suggest that Daurian Redstarts are breeding in places that allow them both access to on forests and also a close relationship with human activity
We reviewed observation records of the Red-billed Blue Magpie Urocissa erythrorhyncha (Corvidae) in Shikoku Island, Japan. This species of magpie, which is native to the Asian continent, is considered to have escaped captivity and been naturalized in western Shikoku. Thirty-three records of this species, dating from 2000 to 2017, were collected from Ehime and Kochi Prefectures. Two records of fledglings confirmed successful breeding. The magpie was observed mainly in secondary forest habitat sites, though they also used conifer plantation and farmland. These observations suggest that this naturalized species has become widely distributed in lowlands of western Shikoku Island.
The rock dove Columba livia var. domestica, which is a common feral pigeon species, has a high degree of intraspecific variation in plumage coloration. Although there are many studies on this topic, the last research in Japan was made approximately 40 years ago. In this study, we compared the ratio of color plumage polymorphism of the rock dove between Tokyo and Osaka. We counted the number of pigeons with each plumage variation (“blue bar”, “check”, “black” and “others”; Electronic Appendix 1) at six sites in Tokyo and three sites in Osaka. We found that the proportion of blue bar type, which are known as the wild type, was lower in Tokyo than in Osaka. In addition, we surveyed the photographs of feral pigeons from past newspaper articles. The results showed that the proportion of blue bar type has decreased between the 1930s and 2000s in Tokyo, but the reason is unknown.
To examine avian flight characteristics of species at risk for bird strikes on tall structure such as power-generating wind turbines, we used GPS transmitters to track the flight behavior of five Whooper Swans Cygnus cygnus and two Northern Pintails Anas acuta at Lake Izunuma, Miyagi Prefecture, a wintering site in Northern Japan. During 2017, the five swans were tracked during a total of seven daily flights between roosting and foraging sites, and pintails were tracked twice. On average, the swans increased their flight altitude by 20.4 ± 6.7 (SD) m per km after takeoff (n=7), and Northern Pintails increased altitude more quickly (47.3 & 99.5 m / km) (n=2). Swans gradually and steadily increased flight altitude until finally taking a landing posture to descend. The swans’ rate of altitudinal increase was clearly lower than the sustainable increase estimated from the dynamic model (Pennycuick 2008, Pennycuick et al. 2013). These results suggest a need to clarify why swans do not increase their altitude as fast as predicted by the dynamic model, with the goal of developing strategies to reduce the risk of bird strike.
This location-related GPS data set for a Whooper Swan Cygnus Cygnus, tracked in Japan in 2016, is provided here to benefit public research. The swan was attached with GPS at the Uchinuma Pond, Miyagi Prefecture, northern Japan. It moved south to Otsuka Pond, Ibaraki Prefecture, where it over-wintered. It then moved to southern Sakhalin via Tokachi, Hokkaido, in March 2017. As it entered Sakhalin, Russia, the swan went out of the GPS-tracking coverage area, and we could not follow the route further north. Although many swans have been satellite tracked before to provide long-distance migration information in East Asia, we are unaware of any GPS-tracking data published to date. GPS data is very detailed and accurate, and has the potential to show details of swan wintering ecology within Japan. Currently, detailed data for swans are of potential value to research in the epidemiology of avian influenza, and to identify the potential impact of wind farm construction on swans. We are providing public access to the data set in order that the public may use it for such purposes.
Data download: http://www.bird-research.jp/appendix/br14/14r01.html