Humpback whales (Megaptera novaeangliae) in the surrounding waters of Isabel Island in western-central Mexico: unveiling a little-known wintering area

The humpback whales which breed in the Mexican Pacific represent an important fraction (~38%) of the estimated population of the North Pacific. Despite the importance of Mexican waters for the reproductive habits of this species, little is known about the ecology of these whales, along the continental coast of Mexico. We analysed the temporal variation of abundance, group types, and inter- and intra-annual recapture rates in the waters adjacent to Isabel Island National Park as well as intra- and inter-seasonal movements with Banderas Bay breeding areas. Inter- and intra-annual recapture rates in Isabel Island National Park were low (1.8%); while 34% of 222 individuals photo-identified in Isabel Island National Park were also recaptured in Banderas Bay. Groups with calves were uncommon (9.5%), while pairs (33.5%) and competitive groups (29.5%) were more common. Intense singing activity was detected in the waters adjacent to Isabel Island. These waters seem to function as a reproductive corridor for the so-called ‘coastal stock’ of humpback whales in the waters adjacent to the continental coast of the Mexican Pacific. Therefore, mid- and long-term studies are needed to understand the dynamics of these displacements. Our findings suggest that Isabel Island National Park is an important area for the mating ecology of the humpback whales of the continental waters of the Mexican coast, and support the initiative to incorporate a Marine Protected Area within the Isabel Island National Park.

Changing winter diet of thick-billed murres Uria lomvia in Southwest Greenland, 1990s versus 2010s

Southwest Greenland constitutes an internationally important wintering area for seabirds, including thick-billed murres (Uria lomvia Linnaeus, 1758), but their prey may be affected by the general warming of this sub-Arctic region. We compare murre diet collected in winter in the 1990s and 2010s around Nuuk. Fish made up 36% of the diet (wet mass) and crustaceans 63% in the 1990s, changing to 22% and 78% in the 2010s, respectively. Capelin (Mallotus villosus Müller, 1776) was the dominant fish species, and the smaller contribution in the 2010s coincided with declining densities of capelin around Nuuk. The crustaceans were dominated by two krill species, Meganyctiphanes norvegica M. Sars, 1857, and Thysanoessa inermis Krøyer, 1846. However, M. norvegica was only important in the 2010s (51% wet mass), while T. inermis was dominating the 1990s with 62% wet mass and only 23% in 2010s. The dominance of M. norvegica in the 2010s confirmed our expectations of a gradual “borealization” of this region due to the generally warming sub-Arctic. The smaller contribution of fish in the diet may also support the hypothesis of deteriorating winter conditions for murres. Apart from the diet, plastic was found in 15% of the birds and 53% had parasitic nematods.

Virio- and bacterioplankton of the Barents Sea in the autumn

The water area of the Kola Bay is an important place for marine and near-water birds during spring-autumn migrations and wintering periods. The results of counts of wintering birds in different parts of the bay in 2020–2021 are presented. The observations were carried out on the coast areas of the bay with the adjacent water area (Gryaznaya Bay, the area of the Kola Bridge). In general, in the southern and middle parts of the Kola Bay, the most numerous species in winter were common eider Somateria mollissima,long-tailed duck Clangula hyemalis, mallard Anas platyrhynchos, and glaucous gull Larus hyperboreus. During the observations, a relatively low nymber of wintering purple sandpipers Calidris maritima was noted in comparison to previous years. The composition of the bird fauna in the Kola Bay is fairly constant during the winter. Abrupt weather changes, such as warming, cooling, or snowstorms, c ause only small movements of birds within the wintering area.

Variation in winter site fidelity within and among individuals influences movement behavior in a partially migratory ungulate

Many animals migrate to take advantage of temporal and spatial variability in resources. These benefits are offset with costs like increased energetic expenditure and travel through unfamiliar areas. Differences in the cost-benefit ratio for individuals may lead to partial migration with one portion of a population migrating while another does not. We investigated migration dynamics and winter site fidelity for a long-distance partial migrant, barren ground caribou (Rangifer tarandus granti) of the Teshekpuk Caribou Herd in northern Alaska. We used GPS telemetry for 76 female caribou over 164 annual movement trajectories to identify timing and location of migration and winter use, proportion of migrants, and fidelity to different herd wintering areas. We found within-individual variation in movement behavior and wintering area use by the Teshekpuk Caribou Herd, adding caribou to the growing list of ungulates that can exhibit migratory plasticity. Using a first passage time–net squared displacement approach, we classified 78.7% of annual movement paths as migration, 11.6% as residency, and 9.8% as another strategy. Timing and distance of migration varied by season and wintering area. Duration of migration was longer for fall migration than for spring, which may relate to the latter featuring more directed movement. Caribou utilized four wintering areas, with multiple areas used each year. This variation occurred not just among different individuals, but state sequence analyses indicated low fidelity of individuals to wintering areas among years. Variability in movement behavior can have fitness consequences. As caribou face the pressures of a rapidly warming Arctic and ongoing human development and activities, further research is needed to investigate what factors influence this diversity of behaviors in Alaska and across the circumpolar Arctic.

Multi-species prey dynamics influence local survival in resident and wintering generalist predators

Stochasticity in food availability influences vital rates such as survival and fertility. Life-history theory predicts that in long-lived organisms, survival should be buffered against environmental stochasticity showing little temporal variability. Furthermore, to optimize survival prospects, many animal species perform migrations to wintering areas where food availability is larger. Species with large latitudinal distribution ranges may show populations that migrate and others that are resident, and they may co-occur in winter. One example of these species is the predatory raptor buzzard Buteo buteo. Here, we test whether temporal variability in the density of five small mammal species of prey inhabiting different habitats (shrubland and forests) influences local annual survival of buzzards in a wintering area depending on their age and residency status (residents versus wintering individuals). We found that prey density explained a considerable amount of annual changes in local survival, which was higher for older and resident birds. This difference in local survival likely corresponded to philopatry to the wintering area, which was larger for residents and increased when prey density was larger. The total density of prey inhabiting open shrublands was the variable explaining more variance in temporal variability of local survival, even though the study area is mostly occupied by woodlands. Temporal population dynamics of the different small mammals inhabiting shrublands were not synchronous, which suggests that buzzards preyed opportunistically on the most abundant prey each winter. Generalist predation may buffer the impact of resource unpredictability for pulsed and asynchronous prey dynamics, typical of small mammals in winter.

Common Eider Wintering Trends in Nova Scotia, 1970–2019

Common eiders Somateria mollissima have been a focus of conservation and management efforts in eastern North American for over a century; however, the complex population structure and multiple subspecies make assessing the status of populations challenging. The coastlines of Nova Scotia, Canada, are an important wintering area for common eiders, and significant harvests of common eiders occur in the province. We analyzed trends in the number of wintering common eiders using the coasts of Nova Scotia from dedicated waterfowl surveys flown since 1970, and every year since 1992. We used Generalized Additive Models to assess the apparent non-linear trends in the counts of common eiders over the past 50 y. We found that numbers of common eiders wintering in Nova Scotia increased from 1970 to the early 2010s, with strong growth in the 2000s (peaking at 7% growth/y). Since the early 2010s, the growth has stopped, and the numbers are now declining. Recent declines in the population wintering in Nova Scotia corroborate other evidence that common eiders are declining in the region, and may also indicate distributional shifts of common eiders in eastern North America.

Movements of a male greater spotted eagle (Clanga clanga) during its 2nd and 3rd calendar years

The greater spotted eagle (Clanga clanga) is poorly known compared to other European eagles. We tracked an immature greater spotted eagle during 2018–2020 within the eastern European part of the species’ distribution, west of the Ural Mountains. Because so little is published about the annual movements of this species, especially from that region, tracking data from this single individual are valuable. 95% kernel density estimator (KDE) range sizes for the two complete winters in Yemen were 4,009 km2 (2018), 1,889 km2 (2019); 95% dynamic Brownian bridge movement models (dBBMM) encompassed 1,309 km2 (2018) and 1,517 km2 (2019). It returned to the same wintering area every year. During summer 2018, it settled into a small area (95% KDE = 126 km2; 95% dBBMM = 21 km2) near Birsk, eastern European Russia; in 2019 it wandered over a huge area (95% dBBMM = 66,304 km2) of western Kazakhstan and southern Russia, south west of Yekaterinburg. Spring migration 2018 was west of the Caspian Sea; during 2019 it was east of it. Mean speed of spring migration was 160±120 km/day during 2018, and 132±109 km/day during 2019. Autumn migration passed east of the Caspian in both years, and the mean speed of migration was 62 ± 78 km/day in 2018, and 84 ± 95 km/day in 2019. During both spring and autumn migrations, the eagle made stopovers, mostly lasting 1–2 days. The eastern Alborz Mountains in northeastern Iran appeared to be an important stopover locale, where autumn stopovers lasted 19 days (2018) and 27 days (2019). These and other data suggest that most greater spotted eagles that spend summers west of about 42°E, winter in southern Europe, Asian Turkey, the Levant and Africa, and those that summer to the east of that meridian winter in southern Asia, including Arabia.

The Effects of Wetland Droughts on a Reserve in the African Continent

Climate change and its attendant fallouts such as drought, flood etc affect every aspects of environment including wetland ecosystem. This paper seeks to examine the effects of droughts on Dagona Waterfowl Sanctuary−an important wintering area for migratory birds in Bade local government, Yobe state, Nigeria. The study used annual rainfall data collected from the archives of the Nigerian Meteorological Agency (NIMET) with respect to Nguru weather station in the area for a period of 1956-2015. Standardized Precipitation Index (SPI) in conjunction with Percentage Deviation Below Mean (PDBM) models were applied for comprehensive drought detection on a time scale of twelve (12) months. SPI anomaly graphs were plotted to depict drought of varying magnitude. The researcher went round the sanctuary and made observations with the help of binocular and telescope. Findings explicitly revealed that the study area was replete with droughts of varying intensities ranging from mild, moderate, severe and extreme ones. And high magnitude droughts led to hydrological changes causing drying up of wetland water, decreased production of seeds that provide forage opportunities, intrusion of invasive species such as typha grasses forming dense biomass that hinder birds to prey on fishes or swim freely. The result of the analysis would add to the mainstream theoretical body of knowledge about droughts effects on wetlands. The research concludes that droughts of high magnitude occurred variably and affected both native and migratory birds in the study area and hence recommend the integration of disasters like drought in the management strategies of the wetlands.

Transcontinental 2200 km migration of a Nathusius’ pipistrelle (Pipistrellus nathusii) across Europe

A male Pipistrellus nathusii ringed in Pape Natural Park (S Latvia) in August 2015 was recovered recently dead in Pitillas’ Lagoon Natural Reserve (N Spain) in March 2017. At 2224 km in SSW direction, this is the first documented bat migration between these countries and worldwide the longest migration record of a bat. We also report other observations of this species in autumn in Northern Spain, suggesting that the Iberian Peninsula may be an important wintering area for Nathusius’ pipistrelles. Conservation measures should be agreed on by countries along the migration routes to improve the protection of this species.