second model, the two main conditions were parametrically modulated by the two categories, respectively (SOM, S5.1). The activation of the precuneus was higher for hard dominance-solvable games than for easy ones ( Fig. 4A and table S10). The activation of the insula was higher for the highly focal coordination games than for less focal ones ( Fig. 4B and table S11). Previous studies also found that precuneus activity increased when the number of planned moves increased (40, 41). The higher demand for memory-related imagery and memory retrieval may explain the greater precuneus activation in hard dominance-solvable games. In highly focal coordination games, the participants may have felt quite strongly that the pool students must notice the same salient feature. This may explain why insula activation correlates with NCI.Participants might have disagreed about which games were difficult. We built a third model to investigate whether the frontoparietal activation correlates with how hard a dominance-solvable game is and whether the activation in insula and ACC correlates with how easy a coordination game is. Here, the two main conditions were parametrically modulated by each participant's probability of obtaining a reward in each game (SOM, S2.2 and S5.2). We found a negative correlation between the activation of the precuneus and the participant's probability of obtaining a reward in dominance-solvable games ( Fig. 4C and table S12), which suggests that dominance-solvable games that yielded lower payoffs presented harder mental challenges. In a previous study on working memory, precuneus activity positively correlated with response times, a measure of mental effort (24). Both findings are consistent with the interpretation that subjective measures reflecting harder tasks (higher efforts) correlate with activation in precuneus. A positive correlation between insula activation and the participant's probability of obtaining a reward again suggests that coordination games with a highly salient feature strongly activated the "gut feeling" reported by many participants (Fig. 4D and table S13). A previous study found that the subjective rating of "chills intensity" in music correlates with activation of insula (42). Both findings are consistent with the interpretation that the subjective intensity of how salient a stimulus is correlates with activation in insula.As mentioned, choices were made significantly faster in coordination games than in dominancesolvable games. The results of the second and third models provide additional support for the idea that intuitive and deliberative mental processes have quite different properties. The "slow and effortful" process was more heavily taxed when the dominance-solvable games were harder. The "fast and effortless" process was more strongly activated when coordination was easy.

Colonial breeding is widespread among animals. Some, such as eusocial insects, may use agonistic behavior to partition available foraging habitat into mutually exclusive territories; others, such as breeding seabirds, do not. We found that northern gannets, satellite-tracked from twelve neighboring colonies, nonetheless forage in largely mutually exclusive areas and that these colony-specific home ranges are determined by densitydependent competition. This segregation may be enhanced by individual-level public information transfer, leading to cultural evolution and divergence among colonies.Main Text: Colonial animals are constrained by their colony locations, which are ultimately limited by resource availability (1). However, within species, potential colony home ranges often overlap, implying competition among colonies may also be limiting (2). In eusocial central-place foragers the spatial effects of direct competition among colonies are well understood (2). In contrast, the spatial influences of indirect competition and information transfer on non-territorial species (e.g. seals, swallows and seabirds), where levels of relatedness are much lower, remain conjectural. For example, the hinterland model (3) predicts that breeding seabirds segregate along colonial lines, because of inequalities in travel costs from each colony. Predicted home ranges therefore comprise Voronoi polygons (Fig. 1A), as seen in some territorial animals (2). Food availability is assumed to be proportional to polygon area, limiting colony size. An alternative model proposes that density-dependent competition among colony members is limiting (4). As colonies grow, local prey depletion or disturbance requires birds to travel further to provision their young. However, this model ('Ashmole's halo') does not consider interactions among colonies and tacitly assumes that adjacent colonies' home ranges overlap (5).Indirect evidence exists to support both models (3,6,7) and recent tracking studies suggest that seabirds and pinnipeds segregate along colonial lines (8-12). However, these studies proved inconclusive on the causes and ubiquity of segregation, largely because few colonies were sampled or tracking resolution was low. Here we use high resolution satellite-tracks of the foraging movements of 184 chick-rearing northern gannets Morus bassanus (hereafter gannets) from 12 of the 26 colonies fringing the British Isles (median 17 birds/colony), representing ~80% of the area's breeding population (Fig. 1A, Table S1), to test whether among-colony segregation occurs in a model colonial non-territorial central-place forager. We then use population-and individual-level models to explore potential mechanisms underlying spatial segregation.Gannets are wide-ranging (max. foraging range ~700 km) pelagic seabirds that forage in patches of enhanced production, primarily on shoaling, mesotrophic fish and to a lesser extent fisheries discards (13)(14)(15). In almost all cases we tracked birds from adjacent colonies simultaneously (16). Individua...

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SUMMARY Many different physiological changes have been observed in wild waterfowl during the flightless stage of wing moult, including a loss of body mass. We aimed to determine whether captive barnacle geese (Branta leucopsis)would show the characteristic decrease in body mass during their wing moult,even though they had unlimited and unrestricted access to food. Fourteen captive geese were weighed at 1–2-week intervals for two complete years. During the flightless period of the moult, body mass decreased by approximately 25% from the pre-moult value. To understand the basis of this change, the rate of oxygen consumption was measured during daytime and nighttime at six points in the second year, and at three points (before,during and after wing moult) behavioural observations were made. Measurements of the rate of oxygen consumption showed an 80% increase above that of the nonmoulting periods of the year. We propose that metabolism was increased during moult because of the cost of feather synthesis. Although food was available, the captive birds chose not to forage and instead increased the proportion of time spent resting. It is likely that this behaviour in response to wing moult is a strategy to avoid predation in the wild. Thus, the innate nature of this behaviour has potential survival value for wild birds of this species. We conclude that the increase in metabolism led to the use of endogenous energy reserves because the birds reduced rather than increased their food intake rates, and as a result, the barnacle geese lost body mass during wing moult.