@article {41711, title = {Social context modulates digestive efficiency in greylag geese (Anser anser)}, journal = {Scientific Reports}, volume = {8}, year = {2018}, month = {11/2018}, pages = {16498}, 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.

}, doi = {10.1038/s41598-018-34337-3}, url = {https://www.nature.com/articles/s41598-018-34337-3.pdf}, author = {Frigerio, Didone and Kotrschal, Kurt and Fabro, Carla and Puehringer-Sturmayr, Verena and Iaiza, Lara and Hemetsberger, Josef and Mason, Federico and Sarnataro, Chiara and Filacorda, Stefano} } @article {41710, title = {Home ranges and movements of resident graylag geese (Anser anser) in breeding and winter habitats in Bavaria, South Germany}, journal = {PloS one}, volume = {13}, year = {2018}, month = {09/2018}, pages = {e0202443}, abstract = {

In several countries in northwestern Europe, the number of resident greylag geese (Anser anser) has increased by up to 20\% a year over the last few decades. The increasing numbers of geese are causing problems in tourism and agriculture. The number of resident greylag geese visiting the Altmuehlsee lake, a recreational area in the south of Germany, has also increased, especially in June and July. However, the geese leave the lake again at the beginning of August. 30 adult greylag geese were banded with telemetry transmitters during molting at the Altmuehlsee lake to determine when the geese leave the lake in August and what structures they need in their winter habitat. The distances the greylag geese flew from their resting sites to foraging sites were calculated, as well as the size of their home ranges and the proportions of each habitat type in the home range. It was found that the greylag geese used small home ranges while rearing their young, and fed close to the water. After molting, the size of their home ranges increased. They fed on fields and meadows around the lake. In the winter habitat, the geese also had a small home range, and they preferred eating grain and corn and the availability of an open body of water. In addition, one group of geese remained in the city of Munich during the winter, benefiting from supplementary food from people. This information helps us to understand the different requirements of resident greylag geese. It can be used to inform management decisions aimed at preventing agricultural damage. Special goose areas can for example be designated for the different periods in a goose\’s life cycle.

}, doi = {https://doi.org/10.1371/journal.pone.0202443}, author = {Kleinhenz, Anke and Koenig, Andreas} } @article {41709, title = {High densities of water-birds at two New Zealand fresh-water urban lakes}, journal = {Notornis}, volume = {65}, year = {2018}, pages = {84{\textendash}91}, abstract = {

Abstract We compared summer counts of water-birds (November\–January, 2012\–2016; mainly Anatidae, Phalacrocoracidae,
Rallidae, Laridae) at 2 small, shallow, urban lakes set in parkland surroundings: Western Springs Lake (Auckland)
and Henley Lake (Masterton), New Zealand. We recorded 25 species of water-birds; 17 at Western Springs Lake and 22
at Henley Lake, with 14 species in common. The average total densities (and biomasses) were 61 birds/ha (113 kg/ha) at
Western Springs Lake, significantly higher than the 40 birds/ha (95 kg/ha) at Henley Lake. Ducks (Tadorninae, Anatinae)
made the biggest single contribution to numbers at both lakes (40\–60\% of total water-bird density). Swans and geese (Anserinae)
were less common than ducks but because they were heavier birds they accounted for 60\–70\% of total biomass,
and were therefore the main consumers of food and producers of droppings. Introduced water-birds made up 60\–70\% of
the density at both lakes, and 80\–90\% of the biomass, with no significant differences between lakes. The presence of some
native species (in significantly greater total density and biomass at Western Springs Lake), and breeding of the endemic
New Zealand scaup at both sites, illustrate the potential conservation value of New Zealand\’s small urban lakes.

}, keywords = {aquatic birds, Biomass, Density, Henley Lake, Waterfowl, Western Springs Lake}, issn = {0029-4470}, author = {Gill, BJ and West, RC} }