Migratory Species Show Distinct Patterns in Corticosterone Levels during Spring and Autumn Migrations

Twice a year billions of birds migrate between breeding and wintering grounds. To facilitate migrations, birds develop migratory disposition, a complex suite of behavioral and physiological adjustments. Glucocorticoid hormone corticosterone is involved in the regulation of migratory behavior and physiology, however no consensus on its exact role in controlling avian migration exists. Using a large dataset on seven songbird species (long- and short-distance migrants) obtained during eleven consecutive migratory seasons on the Courish Spit of the Baltic Sea, we showed the general tendency of similar baseline corticosterone concentrations during both migrations, although stress-induced levels were generally much higher during spring. No difference between long- and short-distance migrants was found in either baseline or stress-induced levels, while there was substantial between-species variation, especially in baseline concentrations. The distinct patterns of corticosterone secretion during seasonal migrations even in ecologically similar species indicate that it is likely to be a species-specific trait. Thus, our study corroborates the inconsistency found in earlier studies and demonstrates how scientific understanding of the role of corticosterone during migration is still evolving. Rather low baseline corticosterone concentrations observed in this study emphasize that birds in both migratory seasons were not in a “stressed” state before capture

The Long-Term Monitoring of Bird Populations on Kolguev Island in the Barents Sea

Kolguev Island (69˚05′ N 49˚15′ E) is located in the Pechora Sea, the southeastern part of the Barents Sea. The island’s ecosystem is unusual due to the total absence of rodents and specialized predators such as weasels, while non-specialized predators such as Arctic (Vulpes lagopus) and red (V. vulpes) foxes and Rough-legged Hawk (Buteo lagopus) are common. Currently, 111 bird species have been registered here, of which 58 are nesting. The absence of rodents and the relatively stable predation pressure have resulted in the high abundance of many bird species: Willow Ptarmigan (Lagopus lagopus), several goose species, some waders, and passerines. Over the 125-year history of ornithological studies on Kolguev, the island avifauna has changed significantly. The trend of an increase in the proportion of widespread and Siberian species together with a decrease in the proportion of Arctic species was observed. Since 2006, a thorough monitoring of Kolguev avifauna has been carried out, during which the dynamics of the bird population densities have been traced. The abundance of Black-bellied Plover (Pluvialis squatarola) and Dunlin (Calidris alpina) decreased, while the numbers of Barnacle Goose (Branta leucopsis) have increased sharply since the 1980s. The breeding density of Rough-legged Hawk has also increased in recent years. The long-term monitoring of Kolguev ecosystems has indicated the high international conservation value of the island due to the high breeding density of many bird species. Our study, covering more than a century of avifaunal studies with almost annual monitoring over the past three decades, provides an unusually long and detailed time-series for an Arctic island.L’île de Kolgouev (69˚05ʹ N 49˚15ʹ E) se situe dans la mer de Pechora, dans la partie sud-est de la mer de Barents. L’écosystème de l’île est inhabituel en raison de l’absence totale de rongeurs et de prédateurs spécialisés comme la belette, tandis que les prédateurs non spécialisés comme le renard arctique (Vulpes lagopus), le renard roux (V. vulpes) et la buse pattue (Buteo lagopus) sont communs. À présent, 111 espèces d’oiseaux ont été enregistrées ici, dont 58 y nichent. L’absence de rongeurs et la pression relativement stable exercée par les prédateurs ont donné lieu à la grande abondance de nombreuses espèces d’oiseaux, soit les lagopèdes des saules (Lagopus lagopus), plusieurs espèces d’oies, certains échassiers et des passereaux. Au cours de l’histoire des études ornithologiques de Kolgouev échelonnée sur 125 ans, la faune aviaire de l’île a changé considérablement. On y observe une tendance vers l’augmentation de la proportion d’espèces répandues et d’espèces sibériennes, et vers la diminution de la proportion d’espèces de l’Arctique. Depuis 2006, la faune aviaire de l’île de Kolgouev a fait l’objet d’une surveillance rigoureuse, ce qui a permis de tracer la dynamique des densités des populations d’oiseaux. L’abondance de pluviers argentés (Pluvialis squatarola) et de bécasseaux variables (Calidris alpina) a diminué, tandis que le nombre de bernaches nonnettes (Branta leucopsis) s’est accru brusquement depuis les années 1980. Par ailleurs, la densité de reproduction de la buse pattue a augmenté ces dernières années. La surveillance à long terme des écosystèmes de Kolgouev témoigne de la forte valeur de conservation de cette île à l’échelle internationale en raison de la densité de reproduction de nombreuses espèces d’oiseaux. Notre étude, qui porte sur plus d’un siècle d’études de la faune aviaire ayant fait l’objet de travaux de surveillance quasi annuels au cours des trois décennies, fournit une série chronologique inhabituellement longue et détaillée pour une île de l’Arctique.Остров Колгуев (69˚05′ с. ш., 49˚15′ в. д.) расположен в Печорском море, в юго-восточной части Баренцева моря. Экосистема острова нетипична ввиду полного отсутствия грызунов и таких специализированных миофагов, как мелкие куньи. В то же время на острове обычны такие неспециализированные хищники, как песец (Vulpes lagopus) и обыкновенная лисица (V. vulpes), а также не менее характерным обитателем острова является зимняк (Buteo lagopus). В настоящее время здесь зарегистрировано 111 видов птиц из них 58 гнездящихся. Отсутствие грызунов и относительно стабильный пресс хищников привели к высокой численности многих видов птиц: белой куропатки (Lagopus lagopus), нескольких видов гусей, некоторых куликов и воробьиных. За более чем столетнюю историю орнитологических исследований на острове Колгуев орнитофауна острова претерпела существенные изменения. Наблюдается тенденция к увеличению доли широкоареальных и сибирских видов при уменьшении доли арктических видов. С 2006 года проводится тщательный мониторинг орнитофауны Колгуева, в течение которого удалось проследить динамику плотности населения птиц. Численность некоторых куликов (тулес (Pluvialis squatarola), чернозобик (Calidris alpina)) снизилась, в то время как численность белощекой казарки (Branta leucopsis) резко возросла с первой регистрации гнездования этого вида на острове в 1980-х гг. В последние годы также существенно увеличилась плотность гнездования зимняка. Долговременный мониторинг экосистем Колгуева показал высокую международную природоохранную ценность острова из-за высокой плотности гнездования многих видов птиц. Наше исследование, охватывающее более чем вековой период орнитологических исследований с почти ежегодным мониторингом в течение последних трех десятилетий, обеспечивает необычайно длинные и подробные временные ряды для арктического острова

Stressed by Maternity: Changes of Cortisol Level in Lactating Domestic Cats

Lactation is the most energetically expensive component of maternal care in mammals. Increased reproductive investment can lead to physiological stress for the mothers, based on the exhaustion of energy resources and increase in glucocorticoids level. This study aimed to estimate the changes in cortisol concentrations during lactation in domestic cats and compared the differences among litter sizes. Eleven females gave birth to 27 litters, which were divided in two groups—small (1–3 kittens) and large (4–7 kittens) litters. Blood samples were collected from each female before mating, after parturition, at 4 and 8 weeks of lactation. We showed that the cortisol level in females changed significantly during lactation—the highest concentrations were observed at the peak of lactation at 4 weeks. Cortisol levels varied significantly among females but did not depend on their maternal experience. We also revealed that there were no differences in cortisol levels between females with small and large litters, but at 4 weeks of lactation, the hormone concentrations were higher in females with small litters. It is likely that these females initially invested less in reproduction, giving birth to fewer offspring

Severe feather deformation in greater white-fronted goose (Anser alb. albifrons) goslings during hot summer period on Kolguev Island 2016

In summer 2016, we observed premature feather malformation among goslings of greater white-fronted goose (Anser alb. albifrons), between 7 and 10 weeks of age on family gathering areas on Kolguev Island, Russia, the most important breeding island in the Western Palearctic. Rarely reported in wild birds, to our knowledge, this phenomenon has not been recorded in wild geese of this species, despite continuous ringing and marking of thousands of wild geese across Northern Europe and Arctic Siberia. This feather malformations were documented in 36 unfledged goslings showing weak feather basis, deformed or unevenly grown wing feathers or even dead feather buds. Approximately about one-third of all chicks were affected. Feather malformations like this, causing flightless chicks as a result, have never been noticed in any other of our 12 study years since 2006. The lesion was characterised by soft feather buds, weak or incomplete wing feathers and lack of feather development. No other abnormalities were observed in the goslings, so goslings did not differ in weight or body sizes. Affected fledglings never became airworthy and were killed in large numbers by predators or at latest perished during the Arctic winter

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

Arctic birds migrating southwards face a multitude of challenges such as habitat loss, pollution, overexploitation of food resources and climate change impacts. Long-tailed Duck winter populations in the Baltic Sea have declined in recent decades. However, precise spatial data are lacking, especially from males. Thus, we aimed to identify the wintering grounds, timing of migration and stopover sites of males and females. We studied spatiotemporal distribution patterns of eight male and five female Long-tailed Ducks using implanted ARGOS satellite transmitters. Birds were tagged in the breeding season on Kolguev Island, Russia. After the breeding period, Long-tailed Ducks from Kolguev used three main post-breeding areas: most males undertook long distance eastward post-breeding migration to areas around the Yamal and Gydan peninsulas, while one male and four females moved short to the southeast coast of Kolguev, and one female moved to Mezhdusharsky Island in the Novaya Zemlya Archipelago. Autumn migration included stopover sites in the White Sea, Lake Ladoga, the Gulf of Finland and the Gulf of Riga, and all birds except one spent the winter in the southern part of the Baltic Sea, from the Pomeranian coast and Hoburgs bank to the Gulf of Finland. Only one female stayed in the White Sea for the winter. All but one bird used the White Sea as a stopover site in May, suggesting that this area is of special importance

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

Barnacle geese <i>Branta leucopsis</i> breeding on Novaya Zemlya: current distribution and population size estimated from tracking data

The Russian breeding population of barnacle geese Branta leucopsis has shown a rapid increase in numbers since 1980, which has coincided with a southwest-wards breeding range expansion within the Russian Arctic. Here barnacle geese also started to occupy coastal and marsh land habitats, in which they were not know to nest on their traditional breeding grounds. While these changes have been well documented by studies and observations throughout the new breeding range of barnacle geese, observations are lacking from the traditional breeding grounds on Novaya Zemlya, as this area is remote and difficult to access. This is especially relevant given rapid climate warming in this area, which may impact local distribution and population size. We used GPS-tracking and behavioural biologging data from 46 individual barnacle geese captured on their wintering grounds to locate nest sites in the Russian Arctic and study nesting distribution in 2008–2010 and 2018–2020. Extrapolating from nest counts on Kolguev Island, we estimate the breeding population on Novaya Zemlya in 2018–2020 to range around 75,250 pairs although the confidence interval around this estimate was large. A comparison with the historical size of the barnacle goose population suggests an increase in the breeding population on Novaya Zemlya, corresponding with changes in other areas of the breeding range. Our results show that many barnacle geese on Novaya Zemlya currently nest on lowland tundra on Gusinaya Zemlya Peninsula. This region has been occupied by barnacle geese only since 1990 and appears to be mainly available for nesting in years with early spring. Tracking data are a valuable tool to increase our knowledge of remote locations, but counts of breeding individuals or nests are needed to further corroborate estimates of breeding populations based on tracking data

Barnacle geese Branta leucopsis breeding on Novaya Zemlya: current distribution and population size estimated from tracking data

The Russian breeding population of barnacle geese Branta leucopsis has shown a rapid increase in numbers since 1980, which has coincided with a southwest-wards breeding range expansion within the Russian Arctic. Here barnacle geese also started to occupy coastal and marsh land habitats, in which they were not know to nest on their traditional breeding grounds. While these changes have been well documented by studies and observations throughout the new breeding range of barnacle geese, observations are lacking from the traditional breeding grounds on Novaya Zemlya, as this area is remote and difficult to access. This is especially relevant given rapid climate warming in this area, which may impact local distribution and population size. We used GPS-tracking and behavioural biologging data from 46 individual barnacle geese captured on their wintering grounds to locate nest sites in the Russian Arctic and study nesting distribution in 2008–2010 and 2018–2020. Extrapolating from nest counts on Kolguev Island, we estimate the breeding population on Novaya Zemlya in 2018–2020 to range around 75,250 pairs although the confidence interval around this estimate was large. A comparison with the historical size of the barnacle goose population suggests an increase in the breeding population on Novaya Zemlya, corresponding with changes in other areas of the breeding range. Our results show that many barnacle geese on Novaya Zemlya currently nest on lowland tundra on Gusinaya Zemlya Peninsula. This region has been occupied by barnacle geese only since 1990 and appears to be mainly available for nesting in years with early spring. Tracking data are a valuable tool to increase our knowledge of remote locations, but counts of breeding individuals or nests are needed to further corroborate estimates of breeding populations based on tracking data