John D. Goss-Custard

Bio: John D. Goss-Custard is an academic researcher from Strand Bookstore. The author has contributed to research in topics: Oystercatcher & Haematopus ostralegus. The author has an hindex of 34, co-authored 54 publications receiving 5401 citations.

Competition for Food and Interference among Waders

Abstract: main theme of this conference is how the feeding conditions, through their effect on the rate of food intake of individual birds, affects these population processes and so bird density. While factors uninfluenced by bird density (e.g. weather) will affect intake rate, the link between bird density and intake rate could be important to the dynamics of the population because it provides a potential feedback loop. The link may be either positive or negative i.e. an increase in bird density may either increase or decrease the rate of feeding. While positive effects may occur in nature, this paper is concerned only with negative effects. Testing for the existence of these in the field, let alone investigating the processes involved, is normally difficult because both the rates of food intake and food abundance are difficult to measure. Wading birds feeding on invertebrates on estuaries, mainly outside the breeding season, are good subjects for this kind of work because their activities are easily seen and the food supply is relatively simple to measure. This

Interference among Oystercatchers, Haematopus ostralegus, feeding on mussels, Mytilus edulis, on the Exe estuary

Abstract: Observation de kleptoparasitisme chez ces oiseaux et d'une hierarchie de dominance stable et lineaire. Le taux d'ingestion des proies diminue avec l'augmentation de la densite des oiseaux. L'on suggere que la dispersion des huitriers au-dessus du banc de moules peut etre decrite par une modification de la «repartition despotique ideale» proposee par Fretwell

The occurrence and adaptive significance of nocturnal habits in waterfowl

Abstract: Summary This paper reviews the occurrence of nocturnal activity, particularly foraging, in wildfowl (Anseriformes) and shorebirds (Charadrii), and discusses its significance. Many duck species are mainly active at night while others regularly feed during both the day and night. Some ducks and geese are normally day feeders and occasionally forage during darkness. In a few duck species, courtship also has been observed at night. Most shorebirds forage both by day and night, in temperate and in tropical latitudes. Some are mainly crepuscular and nocturnal feeders and also display at dusk and at night. Some species may use their daytime territory at night. A few shorebird species, including some visual peckers and long-billed tactile probers, use the same foraging method to detect and capture food by night as by day. However, some long-billed species that forage visually during daytime modify their feeding techniques and rely completely or partly on tactile means for detecting prey at night. Large eyes seem an advantage to plovers and other sight feeders for night feeding. Numerous touch-sensitive corpuscles in the bill of ducks and many scolopacid species favour tactile feeding. Some ducks, geese and shorebirds may especially use moonlit nights for feeding though, in a few species, moonlight seems to have no effect. The possible role of bioluminescence is also discussed. Nocturnal activity may occur for two reasons. The night may be preferred because foraging is more profitable or safest from predators. Alternatively, birds may be forced to forage at night because they fail to collect all their food requirements during the day. The evidence for both hypotheses is reviewed. Nocturnal activity does appear to allow wildfowl, and perhaps shorebirds, to avoid diurnal predators (including man). Shorebirds, and some ducks also seem to take advantage of prey that are more abundant and/or accessible at night. The main evidence for the supplementary feeding hypothesis comes from studies of seasonal variations in the occurrence of nocturnal feeding, about which rather little is known at present. The increasing availability of modern night-viewing equipment may help to fill this gap. There are two important implications arising from the widespread occurrence of nocturnal activity in wildfowl. Most knowledge on time and energy budgets is based on daytime studies, and so may need to be revised. Wintering dabbling ducks and shorebirds, at least in some regions, may use different habitats by day and by night. If confirmed, there would be a need to preserve some wintering habitats which, although little used by ducks and shorebirds during the day, may be intensively used at night.

Spatially explicit, individual‐based, behavioural models of the annual cycle of two migratory goose populations

Abstract: Summary 1. Behaviour-based models of animal population dynamics provide ecologists with a powerful tool for predicting the response of such populations to both natural and human-induced environmental changes. 2. We developed this approach by addressing two outstanding issues in the application of such models: the need to adopt a large-scale spatially explicit approach, and the need to consider the year-round dynamics of animal populations. 3. Spatially explicit, year-round, behaviour-based models of two populations of arctic-breeding geese, the Svalbard population of the barnacle goose Branta leucopsis and the dark-bellied race of the brent goose Branta bernicla, were developed. Both populations have been the subject of serious conservation concern and are currently a source of increasing conflict with agricultural interests. 4. There was generally good agreement between empirically derived and modelgenerated density-dependent functions, and of seasonal patterns of the distribution and movement of populations within and between sites, and of energy reserve levels within a population. 5. Sensitivity analyses, however, highlighted the importance of accurate parameter estimation with respect to the predictions of such models, and the potential flaws in the predictions of existing models that have not adopted a spatially explicit approach when dealing with wide-ranging migratory populations. 6. The eAect of the removal of a given area of habitat on both populations was predicted to vary depending upon the spatial configuration of the change. This further emphasizes the need for a spatially explicit approach. 7. Both barnacle goose and brent goose populations were predicted to decline following habitat loss in their winter or spring-staging sites. Simulations suggested that barnacle geese might be less vulnerable to winter habitat loss than brent geese. This reflected the relative strengths of the density-dependence of productivity and winter mortality in the two models and provided a clear illustration of the need for a year-round approach to animal population dynamics. 8. We believe that these models, and this approach to understanding the population dynamics of long-distance migrants, will be beneficial in attempting to answer the increasingly urgent and frequent requests to predict the response of such populations to environmental change.

Evolution and the Theory of Games

Abstract: In the Hamadryas baboon, males are substantially larger than females. A troop of baboons is subdivided into a number of ‘one-male groups’, consisting of one adult male and one or more females with their young. The male prevents any of ‘his’ females from moving too far from him. Kummer (1971) performed the following experiment. Two males, A and B, previously unknown to each other, were placed in a large enclosure. Male A was free to move about the enclosure, but male B was shut in a small cage, from which he could observe A but not interfere. A female, unknown to both males, was then placed in the enclosure. Within 20 minutes male A had persuaded the female to accept his ownership. Male B was then released into the open enclosure. Instead of challenging male A , B avoided any contact, accepting A’s ownership.

Tutorial on agent-based modelling and simulation

Abstract: Agent-based modelling and simulation (ABMS) is a relatively new approach to modelling systems composed of autonomous, interacting agents. Agent-based modelling is a way to model the dynamics of complex systems and complex adaptive systems. Such systems often self-organize themselves and create emergent order. Agent-based models also include models of behaviour (human or otherwise) and are used to observe the collective effects of agent behaviours and interactions. The development of agent modelling tools, the availability of micro-data, and advances in computation have made possible a growing number of agent-based applications across a variety of domains and disciplines. This article provides a brief introduction to ABMS, illustrates the main concepts and foundations, discusses some recent applications across a variety of disciplines, and identifies methods and toolkits for developing agent models.

Individual-based modeling and ecology

Abstract: Individual-based modeling is a new, exciting discipline that allows ecologists to explore, using computer simulations, how properties of populations and ecosystems might evolve from the characteristics and behaviors of individual organisms. Individual-based Modeling and Ecology, written by Volker Grimm and Steven F. Railsback, gives an excellent introduction and overview of this field. It should be read by everyone interested in individual-based modeling, and especially by anyone contemplating developing, or being involved with a group developing, an individualbased model.

The evolutionary psychology of facial beauty.

Abstract: What makes a face attractive and why do we have the preferences we do? Emergence of preferences early in development and cross-cultural agreement on attractiveness challenge a long-held view that our preferences reflect arbitrary standards of beauty set by cultures. Averageness, symmetry, and sexual dimorphism are good candidates for biologically based standards of beauty. A critical review and meta-analyses indicate that all three are attractive in both male and female faces and across cultures. Theorists have proposed that face preferences may be adaptations for mate choice because attractive traits signal important aspects of mate quality, such as health. Others have argued that they may simply be by-products of the way brains process information. Although often presented as alternatives, I argue that both kinds of selection pressures may have shaped our perceptions of facial beauty.