Ken-ichi Tokita

Spring Migration Routes of Mallards (Anas platyrhynchos) that Winter in Japan, Determined from Satellite Telemetry

Abstract Wild birds, in particular waterfowl, are common reservoirs of low pathogenic avian influenza viruses, and infected individuals could spread the viruses during migrations. We used satellite telemetry to track the spring migration of the mallard ducks (Anas platyrhynchos) that winter in Japan. We studied their migration routes, distribution of stopover and breeding sites, and timing of migration movements. We tracked 23 mallards from four different wintering sites. Nine of the 23 mallards reached presumable breeding sites, where migration terminated. The migration routes of the birds greatly differed not only among the wintering sites but also within the same wintering site, although the general feature of the routes was shared among birds within the same wintering site. The mallards used several stopover sites, and they typically stayed for a long period (about one to four weeks) at a site between migration intervals of two to three days. Stopover sites were located in northeast Japan, the eastern coastline of South Korea and North Korea, and the interior of Far Eastern Russia. Mallards from three different wintering sites used a stopover area near the middle part of the Ussuri river in Russia. The terminal sites, which were presumably also breeding sites, were distributed widely over northeast Asia and Far Eastern Russia. These results suggest that mallards that winter in Japan originate from breeding areas widely distributed across eastern Asia. Mallards could potentially transmit avian influenza viruses between Japan and a broad region of northeastern Asia.

Migration of Honey-buzzards Pernis apivorus based on satellite tracking

ABSTRACT We satellite-tracked the migration of two adult and one young Honey-buzzards Pernis apivorus between the Japanese breeding ground and Southeast Asia. In autumn migration, the two adults (A1 and A2) migrated across the East China Sea, then through China, the Indochina and Malay Peninsula, and Sumatra. After Sumatra, A1 arrived in Java for the winter, while A2 moved up through Borneo and reached Mindanao, the Philippines. The young honey-buzzard moved along the coast of the South China Sea to reach the Malay Peninsula for the winter. In spring migration, A1 went up the Malay Peninsula, and then took a route different from its autumn route, moving up inland China, down to North and South Korea, and arrived at the previous breeding site in Japan. A2 followed the autumn route and reached a stopover site in Cambodia. After an undetermined radio silence, it was rediscovered back at its breeding area in Japan. The young stayed at the wintering site, making no apparent effort to get back to the breeding area. The sample size is limited, but these results suggest that the migration of Honey-buzzards is remarkably convoluted and varies considerably with bird age and season.

Route and site fidelity of two migratory raptors: Grey-faced Buzzards Butastur indicus and Honey-buzzards Pernis apivorus

ABSTRACT In order to examine fidelity to migration route, breeding, wintering, and stopover sites, we analyzed the migration of two adult Grey-faced Buzzards Butastur indicus and an adult Honey-buzzard Pernis apivorus that were satellite-tracked in East Asia for more than two migration seasons. The Grey-faced Buzzards showed a high degree of route fidelity across seasons and years. On the other hand, the migration routes of the Honey-buzzard were distinctly different between fall and spring seasons, whereas, within each season they were roughly similar between years. All three raptors were strictly faithful to their breeding and wintering sites. They also showed fidelity to several stopover sites in which the raptors stayed for relatively long periods to replenish energy. Our findings have important implications for the conservation of the migratory raptors.

Satellite tracking of migrating Whooper Swans Cygnus cygnus wintering in Japan.

Abstract We satellite-tracked Whooper Swans Cygnus cygnus wintering in northern Japan to document their migration routes and timing, and to identify breeding areas. From 47 swans that we marked at Lake Izunuma-Uchinuma, Miyagi Prefecture, northeast Honshu, and at Lake Kussharo, east Hokkaido, we observed 57 spring and 33 autumn migrations from 2009–2012. In spring, swans migrated north along Sakhalin Island from eastern Hokkaido using stopovers in Sakhalin, at the mouth of the Amur River and in northern coastal areas of the Sea of Okhotsk. They ultimately reached molting/breedmg areas along the Indigirka River and the lower Kolyma River in northern Russia. In autumn, the swans basically reversed the spring migration routes. We identified northern Honshu, eastern Hokkaido, coastal areas in Sakhalin, the lower Amur River and northern coastal areas of the Sea of Okhotsk as the most frequent stopover sites, and the middle reaches of the Indigirka and the lower Kolyma River as presumed breeding sites. Our results are helpful in understanding the distribution of the breeding and stopover sites of Whooper Swans wintering in Japan and in identifying their major migration habitats. Our findings contribute to understanding the potential transmission process of avian influenza viruses potentially carried by swans, and provide information necessary to conserve Whooper Swans in East Asia.

Satellite-Tracking of the Spring Migration and Habitat Use of the Brent Goose Branta bernicla in Japan

Abstract Japan hosts more than 40% population of Brent Goose Branta bernicla wintering in East Asia. We used satellite-tracking technology to monitor the seasonal movements and habitat usage of Brent Goose wintering in northern Japan. We marked five geese on the Oya sandy beach, Miyagi Prefecture, northeast Honshu, on 21 January 2014. The geese utilized areas along the seacoast, especially concentrating at a small bay, close to the capture site. Most of the geese offshore were found at fishery rafts. No geese were found more than 2 km offshore or more than 6 km from the capture site along the seacoast. In early April, the geese left the southern Sanriku coast and moved up to eastern Hokkaido, crossing the sea directly or via the coastal areas of Iwate and Aomori Prefectures. The geese predominantly remained in the vicinity of the Veslovskiy Peninsula, Kunashiri (Kunashir) Island, while some were distributed along the northern coast of the Nemuro Peninsula. We identified eastern Hokkaido and Kunashiri Island as important stopover sites for Brent Goose wintering in Japan.

Spring Migration of Brent Geese Wintering in Japan Extends into Russian High Arctic

Abstract The spring migration routes of the Brent Goose Branta bernicla nigricans wintering in Japan can extend beyond those of earlier-published trajectories from satellite data (Shimada et al. 2016). This conclusion is based on a ring recovered from a goose shot by a hunter, found south of the Lena Delta in the Russian high arctic. Building on the previously published satellite-tracking data from the same population, we suggest that the geese migrate northward in Russia following an interior route along the Lena and Yana rivers after arriving at the northern coast of the Sea of Okhotsk from Japan during spring migration.