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

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