Year-round spatiotemporal distribution pattern of a threatened sea duck species breeding on Kolguev Island, south-eastern Barents Sea

Abstract

Background The long-tailed duck (Clangula hyemalis) was categorized as ´Vulnerable` by the IUCN after a study revealed a rapid wintering population decline of 65% between 1992–1993 and 2007–2009 in the Baltic Sea. As knowledge about the European long-tailed duck’s life cycle and movement ecology is limited, we investigate its year-round spatiotemporal distribution patterns. Specifically, we aimed to identify the wintering grounds, timing of migration and staging of this population via light-level geolocation. Results Of the 48 female long-tailed ducks tagged on Kolguev Island (western Russian Arctic), 19 were recaptured to obtain data. After breeding and moulting at freshwater lakes, ducks went out to sea around Kolguev Island and to marine waters ranging from the White Sea to Novaya Zemlya Archipelago for 33 ± 10 days. After a rapid autumn migration, 18 of 19 birds spent their winter in the Baltic Sea and one bird in the White Sea, where they stayed for 212 ± 3 days. There, they used areas known to host long-tailed ducks, but areas differed among individuals. After a rapid spring migration in mid-May, the birds spent 23 ± 3 days at sea in coastal areas between the White Sea and Kolguev Island, before returning to their freshwater breeding habitats in June. Conclusions The Baltic Sea represents the most important wintering area for female long-tailed ducks from Kolguev Island. Important spring and autumn staging areas include the Barents Sea and the White Sea. Climate change will render these habitats more exposed to human impacts in the form of fisheries, marine traffic and oil exploitation in near future. Threats that now operate in the wintering areas may thus spread to the higher latitude staging areas and further increase the pressure on long-tailed ducks.

Year-round movements of Long-tailed Ducks Clangula hyemalis from Kolguev Island, Barents Sea

“…Small proportions of the flyway population winter outside the Baltic in coastal waters off Norway and the Kola Peninsula (Heggøy and Shimmings 2016), and a few birds stay in ice-free parts of the White Sea (Loshchagina et al 2019;Karwinkel et al 2020). Our present study is the second to find one female from Kolguev wintering in the White Sea, the previous being Karwinkel et al (2020).…”

“…Of the remaining, two birds wintered at the southern coast of Finland, where only low densities of Long-tailed Ducks were recorded in the early 1990s (Durinck et al 1993). At least one other female from Kolguev spent the winter 2017-2018 in this area (Karwinkel et al 2020).…”

“…Small proportions of the flyway population winter outside the Baltic in coastal waters off Norway and the Kola Peninsula (Heggøy and Shimmings 2016), and a few birds stay in ice-free parts of the White Sea (Loshchagina et al 2019;Karwinkel et al 2020). Our present study is the second to find one female from Kolguev wintering in the White Sea, the previous being Karwinkel et al (2020). While both studies together still form a comparatively small sample, it is notable that several birds were found wintering north-east of the core wintering range, in the Gulf of Finland and the White Sea.…”

“…Approximately 90% of this Long-tailed Duck population winter in the Baltic Sea (Skov et al 2011). In a recent tracking study using light-level geolocators, 18 of 19 female Long-tailed Ducks breeding at Kolguev Island in the southeastern Barents Sea spent their winter in the Baltic Sea and one bird in the White Sea (Karwinkel et al 2020). Females were selected for that study because they are faithful to the breeding ground and can be recaptured to remove data loggers.…”

Response of Long-Tailed Duck (Clangula hyemalis) to the Change in the Main Prey Availability in Its Baltic Wintering Ground

“…The first survey took place from 1992 to 1993 and estimated a population of 4.3 million long-tailed ducks wintering in the Baltic Sea [2], while repeated counts in the same areas from 2007 to 2009 recorded a vertiginous population decrease to 1.5 million. This corresponded to a rapid population decline [2,3], in which the abovementioned threat of long-tailed ducks being bycaught in gillnets was found to be responsible for a 1-5% annual decline alone [6]. For these reasons, the long-tailed duck is classified as a 'Vulnerable' species on the IUCN global red list of threatened species [7,8].…”