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.

Effects of Infection-Induced Migration Delays on the Epidemiology of Avian Influenza in Wild Mallard Populations

“…The results of our model are based upon the assumptions that all birds stop at exactly three staging sites. We expect to observe the same trends in infection dynamics for any biologically realistic number of staging sites, for example, as obtained from satellite tracking studies [18], [32]. However any model which does not include staging sites, whereby birds transfer directly back and forth between breeding and wintering grounds, would fail to reproduce the predictions that we have presented here.…”

“…During these migration periods, the birds rest at a handful of staging sites in order to feed and recover. A satellite telemetry study by Yamaguchi et al [18] of mallards which spend winter in Japan suggests that the mean number of staging sites is between 1.3 and 3 depending on the chosen location for breeding and that mallards stay for one to four weeks at each staging site between short travel periods of a few days.…”

“…Instead both spring (northward) and autumn (southward) migration are characterised by a number of flight periods interspersed by periods of refuelling. During these refuelling periods birds congregate in large numbers at staging sites [18]. The clinical effects of infection may lead to a delay in departure from these staging sites for infected individuals.…”

Seroprevalence of West Nile Virus in Wild Birds in Far Eastern Russia Using a Focus Reduction Neutralization Test

“…Recent studies of migration routes of mallard ( Anas platryhynchos ) determined by satellite telemetry have shown that besides the northward flyway from Japan to Russia, a northwestward flyway also exists in Far East Russia. 26 In Japan, WN virus activity has not yet been detected. In the metropolitan area of Tokyo from 2002 to 2006, a total of 7,281 mosquitoes and 139 crow samples (blood, brain, kidney, and spleen) were tested for WN virus RNA, and none of them were positive.…”

Haemagglutinin and neuraminidase characterization of low pathogenic H5 and H7 avian influenza viruses isolated from Northern pintails (Anas acuta) in Japan, with special reference to genomic and biogeographical aspects

“…The feasibility of such relatedness is supported, as well, by the presence of our H5N2 isolate Akita/714/06 H5N2 in Japan in the same host, at the same place, 11 months earlier, considering that pintails wintering in Japan and Korea regularly congregate in their Siberian breeding grounds. This ecoepidemiologic interface may further be enhanced by mallards that seasonally move from Japan to Siberia through Korea [37]. The Japanese-Korean-Siberian phylogeographical axis seems to be, then, particularly important for ongoing generation of novel viral strains through conveyance of certain genes and genomes by migratory ducks, including such that circulate among pigs and human.…”