Social foraging European shags: GPS tracking reveals birds from neighbouring colonies have shared foraging grounds

Developments in tracking technologies have enhanced our understanding of the behaviours of many seabird species. However few studies have examined the social aspects of seabird foraging behaviour, despite the effect this might have on the distribution of foraging areas and the differences that might arise between colonies. Here we use bird-borne GPS and behavioural observation to study the social foraging behaviour and habitat use of breeding shags from three breeding colonies in the Isles of Scilly, UK. Thirteen breeding shags from three colonies (six at two colonies and a single bird from another) were tracked between 2010 and 2012 and related to observations of conspecific foraging aggregations (2013-2014). Tracked shags had short foraging ranges (1.74 ± 1.6 km) mostly travelling to shallow waters between the islands and observations revealed that many shags foraged in large social groups that were consistent in time and space. There were also no clear differences in foraging distributions among colonies—birds shared similar foraging grounds. Our finding provides important insight into the use of social information among foraging seabirds and how this may lead to shared foraging areas, as well as space partitioning

Masking of Several Olfactory Notes by Infra-threshold Concentrations of 2,4,6-Trichloroanisole

Introduction Among wine defects, 2,4,6-trichloroanisole has a specific impact on wine perception. In addition to giving to the wine an unpleasant odor, 2,4,6-trichloroanisole has a masking effect on notes. In this study, the specificity and efficacy of the masking effect of 2,4,6-trichloroanisole was tested at infra- and supra-threshold concentrations. A simplified model of a binary mixture was also studied for in-depth analysis of this phenomenon. Methods Techniques used included sensory analysis (odor profiling), psychophysical tests (threshold measurement and triangle test), chemical analyses (GC-MS), and a mono/dichorhinic stimulation paradigm, to test the hypothesis of peripheral interaction. Results The results revealed that TCA had a masking effect on a range of aromatic notes, even at infra-threshold concentrations. However, they also showed counteraction of odorant specificity by 2,4,6-trichloroanisole. The origin of this masking effect was also discussed. The results suggested that this interaction can be assumed to take place at receptor level. Conclusion This study provided experimental confirmation of the widespread idea that constituents in non-perceptible concentrations influence the perceived quality of mixtures of odorous compounds. Implications Moreover, this type of olfactory model may improve our understanding of combinatorial olfactory encoding at the peripheral level