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Anser Anser

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Kurt Kotrschal – One of the best experts on this subject based on the ideXlab platform.

  • Parental behaviour and family proximity as key to gosling survival in Greylag Geese (Anser Anser).
    Journal of Ornithology, 2019
    Co-Authors: Georgine Szipl, Kurt Kotrschal, Josef Hemetsberger, Claudia A. F. Wascher, Alina Loth, Didone Frigerio

    Abstract:

    Reproductive success in monogamous species is generally affected by both behavioural and hormonal fine-tuning between pair partners. Vigilance, defence and brooding of offspring are among the main parental investments, and often the sexes adopt different roles. In the present study, we investigate how sex differences in parental behaviour and family proximity in the socially monogamous Greylag Goose (Anser Anser) affect gosling survival. During the reproductive season in spring 2013, we recorded the behaviour of 18 pairs with offspring and gosling survival in a semi-tame, long-term monitored, and individually marked flock of Greylag Geese in Grunau, Austria. We found that behavioural role differentiation between the parents varied with developmental phase, and thus with gosling age. Especially during the first 10 days after hatching, females were foraging more frequently than males, which were more vigilant and aggressive towards other flock members. Such differences between the sexes levelled out 20 to 30 days after hatching. In general, females stayed in closer proximity to their offspring than males. Gosling survival was high when the parents were relatively aggressive and emphasized vigilance rather than foraging behaviour. Hence, we show a direct link between pair partners’ quality of parental investment and gosling survival.

  • Social context modulates digestive efficiency in greylag geese (Anser Anser).
    Scientific Reports, 2018
    Co-Authors: Didone Frigerio, Kurt Kotrschal, Carla Fabro, Verena Puehringer-sturmayr, Lara Iaiza, Josef Hemetsberger, Federico Mason, Chiara Sarnataro, Stefano Filacorda

    Abstract:

    In group-living animals, social context is known to modulate physiology, behaviour and reproductive output as well as foraging and nutritional strategies. Here we investigate the digestive efficiency of 38 individuals belonging to different social categories of a semi-feral and individually marked flock of greylag geese (Anser Anser). During 9 consecutive days in winter 2017, when the ground was fully covered with snow (i.e. no grass or other natural forage available) and the accessible food was standardized, 184 individual droppings were collected and analysed to estimate the apparent digestibility of organic matter (ADOM). Lignin was used as an indigestible internal marker in the food and droppings. The digestive efficiency was higher in pairs with offspring as compared to pairs without offspring or unpaired birds. Furthermore, individuals with high ADOM were more likely to breed successfully in the following season than those with low ADOM. Our findings demonstrate that social status modulates digestive efficiency, probably via a chain of physiological mechanisms including a dampened stress response in individuals enjoying stable social relationships with and social support by their family members (i.e. their own pair-partner and offspring). Our findings underline the importance of the social network in modulating physiology, such as digestive efficiency, and ultimately reproductive success.

  • Leucocyte profiles and family size in fledgling greylag geese (Anser Anser)
    Avian Biology Research, 2017
    Co-Authors: Claudia A. F. Wascher, Josef Hemetsberger, Kurt Kotrschal, Didone Frigerio

    Abstract:

    In precocial species large brood sizes are usually considered as beneficial and individuals in larger broods grow faster and are more dominant compared to individuals in small broods. However, little is known whether family size also beneficially affects the offspring’s physiology. In the present study we investigated whether leucocyte profiles in fledgling greylag geese (Anser Anser) are affected by (1) family size, (2) individual characteristics, i.e. age, body condition or sex, or (3) characteristics of the parents, i.e. previous reproductive success. From spring 2013 to fall 2015, we collected blood samples from 100 juvenile greylag geese from 20 different pairs. From these samples we determined the absolute leucocyte number, an individual’s differential blood cells count and an individual’s haematocrit (HCT). The number of fledglings in a family and therefore the number of siblings a focal individual had, was positively related to the percentage of basophils, negatively to the heterophils/lymphocytes ratio (H/L), and tended to be negatively related to the percentage of monocytes and eosinophils in a sample. H/L ratio was negatively related to age in days and tended to be negatively related to body condition, whereas the percentage of basophils tended to be positively related to it. Absolute leucocyte number did not differ between individuals depending on family size. However, composition of different leucocyte types (basophils, eosinophils, H/L ratio) was modulated mostly by the social environment (family size) and not by the characteristics of the individual or the parents. In conclusion, even though we did not find clear evidence of a positive health effect, i.e. a better immune system, in fledgling greylag geese of large versus small families, our results suggest that family size modulates different components of the immune system hinting at its stress-reducing effect.

Leif Nilsson – One of the best experts on this subject based on the ideXlab platform.

  • The establishment of a new major moulting site for Greylag Geese Anser Anser at Lake Hornborgasjön, southern Sweden
    , 2019
    Co-Authors: Leif Nilsson, Clas Hermansson

    Abstract:

    At around 1900, Lake Hornborga in southern Sweden was considered to be one of the best breeding lakes for waterbirds in the country. In subsequent years, the area was drained and lake water levels reduced to avoid flooding and obtain land for farming. By 1950, the remaining lake and wetland area (34 km2) had become a swamp, totally overgrown with reed beds and bushes. The Swedish Environmental Protection Agency initiated a lake restoration project during the 1960s and 1970s and by 1995 the site had been restored to a shallow lake. Greylag Geese Anser Anser started using the lake for breeding and moulting shortly thereafter, and it has attracted increasing numbers of moult migrants over the last 15 years, with 28,000 moulting geese counted in 2015. Neck-banding and collar resightings during 2004–2007 showed that the lake attracted geese not only from south Sweden and Denmark but also from eastern continental Europe (e.g. Poland) to moult. Seventy-two Greylag Geese marked at a study area in Scania, southwest Sweden, have been seen moulting at Lake Hornborgasjon, whereas geese from this area formerly moulted mainly in Flevoland in the Netherlands and later in Denmark. Individual birds from other areas were also shown to have changed their moulting sites in recent years.

  • Lifetime reproductive success of Greylag Geese Anser Anser breeding in south Sweden
    Ornis Svecica, 2018
    Co-Authors: Leif Nilsson, Hakon Kampe-persson

    Abstract:

    During 1984–2009, 664 adults and 1,944 goslings of Greylag Geese Anser Anser were neck-banded in south-west Scania, Sweden. After hatching the area was careful-ly searched for marked geese, giving more than 100,000 re-sightings. Of those marked as goslings 71% survived the first year, 52% the second year, and the oldest bird recorded was 25 years. About 50% of the survivors were recruited into the breeding population when two to three years old. Of 1,187 geese that survived for at least two years, 25% produced at least one brood of small young, and 18% at least one fledged young. The maximum lifetime number of broods with fledged young was nine, but 50% of the geese known to have bred successfully pro- duced only one brood of fledged young. Ten percent of the geese seen with small goslings produced 47% of all fledged young. The maximum number of fledged young for a goose of known age was 32 (age 15 years), but two geese marked as adults and followed for 16 and 17 years produced 40 fledglings each.

  • Changes in abundance and breeding output of Greylag Geese Anser Anser breeding in southern Sweden
    , 2018
    Co-Authors: Leif Nilsson

    Abstract:

    Neck-banded Greylag Geese Anser Anser from a population breeding in southwest Scania, southern Sweden, were studied to assess changes in the breeding population and breeding performance during 1984–2013. The population increased ten-fold during this period, only to decrease again in the later years of the study. Greylag Geese arrived on the breeding grounds about 3–4 weeks earlier by 2007–2009 compared to the 1980s, probably an effect of wintering further north closer to the breeding areas in more recent years. Mean hatch date did not advance significantly over the same period. The proportion of breeding Greylag Geese that produced a brood of small young decreased during the study. On the other hand, the mean brood size at hatching for those succeeding in producing a brood, and the survival of young to fledging amongst marked families, showed no significant trends.

Arne Follestad – One of the best experts on this subject based on the ideXlab platform.

  • Migratory flights and local wintering movements of Greylag Geese Anser Anser in western Europe
    Bird Study, 2019
    Co-Authors: Mathieu Boos, Anna P. Nesterova, Damien Chevallier, Arne Follestad

    Abstract:

    ABSTRACTThe local and migratory movements of Greylag Geese Anser Anser wintering in southwest and northwest Europe were revealed with global positioning system tracking. Geese in the southwest had …

  • Migratory flights and local wintering movements of Greylag Geese Anser Anser in western Europe
    Bird Study, 2019
    Co-Authors: Mathieu Boos, Anna P. Nesterova, Damien Chevallier, Arne Follestad

    Abstract:

    The local and migratory movements of Greylag Geese Anser Anser wintering in southwest and northwest Europe were revealed with global positioning system tracking. Geese in the southwest had smaller home ranges than those from the northwest, and birds also moved large distances over wintering grounds and showed flexibility in the annual choice of wintering sites.

  • Temporal changes in spring migration phenology in the Norwegian Greylag Goose Anser Anser, 1971-2004
    , 2013
    Co-Authors: Pierre A Pistrorius, Arne Follestad, Frances E. Taylor

    Abstract:

    During spring, Greylag Geese Anser Anser migrate from staging grounds in the Netherlands to breeding sites in Norway. The timing of this migration is critical as it corresponds to the most energetically expensive period in the birds’ seasonal cycle, and governs the time available for breeding during the short northern summer. This paper reports how the spring migration and the subsequent breeding season of Greylag Geese nesting in Norway have gradually become earlier since 1971, by about 5–7 days per decade up to 2004. First arrival date, median arrival date and fi rst hatching date at the most important breeding site in Norway were inversely related to spring temperatures in the Netherlands, suggesting that this trend may be a function of climate change.