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Leading researchers in behavioural ecology discuss specific aspects of this important topic including: The mechanism of habitat selection and how it operates Its relevance to population biology Behavioural and physiological implications The ecological and evolutionary significance of habitat choice and survival and reproduction in various habitat types.
Animal foraging behavior not only affects individual fitness of animals but can also mediate the magnitude of granivory and herbivory of plant communities. As a result, understanding how aspects of the environment affect animal foraging behavior is critical to predicting how changes in the environment may directly affect animal populations and indirectly affect plant communities. Since animals must avoid attack by predators or costly encounters with conspecific competitors while foraging, animal behavior may be shaped by characteristics of the environment that predict the likelihood of predation or intraspecific competition. Disturbances, such as fire and forest harvest, can have profound impacts on habitat characteristics (e.g., vegetative concealment from predators) that affect the identity and behavior of animals foraging in a habitat. Moreover, the legacies of historic disturbances, like past agricultural land use in restored habitats, can also impact habitat structure and, as a consequence, animal foraging behavior. By conducting an experiment that coupled canopy harvesting at sites containing both post-agricultural land use and nonagricultural land use, I found that land-use history and canopy harvesting determine the outcomes of seed-granivore interactions by modifying environmental characteristics relevant to mammal behavior. Seed predation rates in harvested plots were positively correlated with cotton rat (Sigmodon hispidus) foraging activity, which was lower in post-agricultural harvested plots than in nonagricultural harvested plots. In unharvested plots, seed predation increased with fox squirrel (Sciurus niger) activity, but fox squirrels were not affected by land-use history. In another experiment that measured white-tailed deer (Odocoileus virginianus) foraging and antipredator behavior across longleaf pine woodlands varying in past land use and contemporary fire frequency, I found that frequent fires generated riskier habitats for deer, but deer utilized different antipredator strategies while foraging in habitats with different land-use histories. Experimental manipulation of acoustic predator cues (i.e., coyote (Canis latrans) vocalizations) revealed that deer only modify their foraging behavior in response to a direct cue of predator activity in frequently burned, nonagricultural woodlands. Long-term herbivore exclosures revealed that deer herbivory only reduced deer-preferred plant species richness in infrequently burned woodlands, where deer perceptions of risk were lower. These results suggest that past and present disturbances can interact to generate "landscapes of fear" in which spatial variation in deer antipredator behavior may help explain large-scale patterns in plant communities. Omnivorous predators, such as coyotes, that consume both animal prey and fleshy fruits may also affect plant communities as agents of seed dispersal. Since coyote foraging decisions determine individual diet and space use, understanding how aspects of the environment affect individual coyote foraging decisions is essential to understanding how environmental changes may affect seed dispersal by coyotes. By experimentally manipulating seed association with coyote scat and granivore access to seeds, I found that seed dispersal in coyote scat reduced predation of larger seeds by rodents but increased predation of smaller seeds by arthropods. Coyote scat composition was also important in affecting rodent seed predation such that seed predation was lower in the presence of meat-rich scat compared with fruit-rich scat. These results illustrate that individual coyote foraging decisions can have cascading effects on seed dispersal and survival. In an experiment evaluating how time of day and conspecific activity affect coyote foraging decisions, I found that coyotes were more likely to investigate experimental resource patches towards the end of the diel activity period and were less likely to consume resources at patches that were visited by other conspecifics. Collectively, these studies illustrate that individual coyote foraging decisions may plan an important role in mediating seed dispersal and survival, and coyote foraging decisions may be shaped by an individual's social environment.
After the breeding season, many bird species move to different habitats or alter their social behavior for the nonbreeding season. High densities of neotropical migrant species funnel into Mexico, Central America, and the West Indies, but relatively little is known about the wintering strategies of these migrants or the permanent resident species. I documented the distribution of migrant species in four habitats in the El Cielo Biosphere Reserve in southern Tamaulipas, Mexico, and studied the structure of mixed-species flocks which consisted of both migrant and Mexican resident species. I used point count surveys and mist nets to determine the distribution of migrant species among tropical semi-deciduous forest (300 m altitude), cloud forest (1100 m altitude), humid oak-pine forest (1200 m altitude), and dry pine-oak forest (1800 m altitude) in the Sierra Madre Oriental mountains. Forty-one species of migrants and 136 species of Mexican residents were observed during the winters of 1993-1995; migrant species represented from 22% to 29% of the species detected in point counts and captured in mist nets. Habitats at higher elevations with temperate-like forests and at lower elevations with tropical forests supported the greatest number and highest abundance of migrant species. Migrants showed some flexibility in habitat use, particularly compared to resident species. Mixed-species flocks, particularly insectivorous foraging flocks, were prevalent during the nonbreeding season in northern Mexico. Flocks in the dry pine-oak forest averaged the most individuals and species per flock. Participants in mixed-species flocks did not appear to be a random collection of species, and niche partitioning by foraging behavior was ubiquitous among flock members. Ruby-crowned kinglet, a migrant species, and crescent-chested warbler, a Mexican resident species, were nuclear flock species in one habitat and follower flock species in another habitat; their foraging behavior also changed among habitats and with different flockmates. Patterns of foraging behavior in mixed-species flocks were consistent with models of competition and habitat selection, but I could not separate the effects of these processes in this system. Survival during the nonbreeding season is critical in maintaining populations; continued studies of winter community structure are important for understanding large-scale population dynamics.
When a predator attacks, prey are faced with a series of 'if', 'when' and 'how' escape decisions – these critical questions are the foci of this book. Cooper and Blumstein bring together a balance of theory and empirical research to summarise over fifty years of scattered research and benchmark current thinking in the rapidly expanding literature on the behavioural ecology of escaping. The book consolidates current and new behaviour models with taxonomically divided empirical chapters that demonstrate the application of escape theory to different groups. The chapters integrate behaviour with physiology, genetics and evolution to lead the reader through the complex decisions faced by prey during a predator attack, examining how these decisions interact with life history and individual variation. The chapter on best practice field methodology and the ideas for future research presented throughout, ensure this volume is practical as well as informative.
Abstract: Grassland birds are declining at greater rates than any other habitat guild in North America, yet conservation remains difficult due to extensive habitat loss and fragmentation throughout the urbanizing Midwest. Human presence is often associated with non-native predators (e.g., cats) and anthropogenic food sources, which collectively can promote high densities of nest predators in urban landscapes. High densities of nest predators are a concern because predation is the leading source of nest failure. Behavioral responses to predators may further diminish the value of urban habitats if birds avoid areas with high levels of predator activity, which could result in lower occupancy rates or densities of birds in urban habitat patches. In my research, I examined how habitat heterogeneity and variation in the predator community influenced the breeding ecology of grassland and early successional birds in urban parks. I asked two broad questions: (1) how do birds respond behaviorally to abundance and activity of predators in urban natural areas? (2) to what extent is avian reproductive success linked to predator communities and/or activity at plot and site scales? I collected data on avian density, nest placement, and reproductive success of eight focal species of grassland birds within 46 2-ha plots at seven urban parks near Chicago, Illinois, during 2009 and 2010. Relative abundance and activity levels of potential nest predator species, including mesopredators, small mammals, snakes, and avian predators, were estimated for each plot during surveys and as part of a collaborative study. As capture rates of small mammals increased, territory densities of Field Sparrow (Spizella pusilla), Common Yellowthroat (Geothlypis trichas), and Savannah Sparrow (Passerculus sandwichensis) declined, but density of Song Sparrow (Melospiza melodia) rose. Mesopredator capture rates were negatively associated with Common Yellowthroat and Savannah Sparrow densities within 2-ha plots, as well as Eastern Meadowlark (Sturnella magna) at the site level. Whereas small mammal and mesopredator capture rates explained some of the observed variation in territory density, daily nest survival of both Field and Song Sparrows was best explained by numbers of snakes observed within plots. Interestingly, snake activity was positively associated with nest survival of Field Sparrows, though negatively associated with that of Song Sparrows. At large scales, vegetation characteristics best predicted nest survival of both species, with nest survival of Field Sparrow improving as density of groundcover increased and nest survival of Song Sparrow improving as structural complexity increased. While the structural complexity of vegetation at nest sites was not explained by predator activity, Song Sparrows selected nest sites with lower groundcover density than available as activity of Brown-headed Cowbird (Molothrus ater) increased. As a whole, these results provide evidence that breeding grassland and early successional birds respond to both habitat structure and activity of potential predators at different scales. I also found that behavioral (e.g., territory selection) and demographic (e.g., nest survival) associations with predators do not necessarily match. For example, snakes had the strongest, though sometimes counterintuitive, relationship with nest success of Field and Song Sparrows, yet appeared to elicit no response during territory or nest site selection. My results are also consistent with other studies demonstrating the importance of vegetation structure to both settlement and reproductive success. Consequently, the best management practices in urban parks will both maintain vegetation structure that promotes successful nesting and discourage activities that promote high abundances of predators.
The classic literature on predation dealt almost exclusively with solitary predators and their prey. Going back to Lotka-Volterra and optimal foraging theory, the theory about predation, including predator-prey population dynamics, was developed for solitary species. Various consequences of sociality for predators have been considered only recently. Similarly, while it was long recognized that prey species can benefit from living in groups, research on the adaptive value of sociality for prey species mostly emerged in the 1970s. The main theme of this book is the various ways that predators and prey may benefit from living in groups. The first part focusses on predators and explores how group membership influences predation success rate, from searching to subduing prey. The second part focusses on how prey in groups can detect and escape predators. The final section explores group size and composition and how individuals respond over evolutionary times to the challenges posed by chasing or being chased by animals in groups. This book will help the reader understand current issues in social predation theory and provide a synthesis of the literature across a broad range of animal taxa. - Includes the whole taxonomical range rather than limiting it to a select few - Features in-depth analysis that allows a better understanding of many subtleties surrounding the issues related to social predation - Presents both models and empirical results while covering the extensive predator and prey literature - Contains extensive illustrations and separate boxes that cover more technical features, i.e., to present models and review results
Mixed-Species Groups of Animals: Behavior, Community Structure, and Conservation presents a comprehensive discussion on the mixed-species groups of animals, a spectacular and accessible example of the complexity of species interactions. They are found in a wide range of animals, including invertebrates, fish, mammals and birds, and in different habitats, both terrestrial and aquatic, throughout the world. While there are more than 500 articles on this subject scattered in separate categories of journals, there has yet to be a general, cross-taxa book-length introduction to this subject that summarizes the behavior and community structure of these groups. The authors first survey the diversity of spatial associations among animals and then concentrate on moving groups. They review the major classes of theories that have been developed to explain their presence, particularly in how groups increase foraging efficiency and decrease predation. Finally, they explore the intricacies of species interactions, such as communication, that explain species roles in groups and discuss what implications these social systems have for conservation. - Functions as a single resource for readers inside and outside of academia on mixed-species groups, serving as a foundation for future research in this field - Begins with an empirical summary of mixed-species distribution and reviews how the theories explaining their adaptive benefits are supported by the evidence - Includes many aspects of mixed-group behavior (e.g. foraging, communication, collective decision-making, dominance, social roles of species and leadership, relationship to conservation) that were not previously or easily accessible
Professor Cody's monograph emphasizes the role of competition at levels above single species populations, and describes how competition, by way of the niche concept, determines the structure of communities. Communities may be understood in terms of resource gradients, or niche dimensions, along which species become segregated through competitive interactions. Most communities appear to exist in three or four such dimensions. The first three chapters describe the resource gradients (habitat types, foraging sites, food types), show what factors restrict species to certain parts of the resource gradients and so determine niche breadths, and illustrate the important role of resource predictability in niche overlap between species for resources they share. Most examples are drawn from eleven North and South American bird communities, although the concepts and methodology are far more general. Next, the optimality of community structure is tested through parallel and convergent evolution on different continents with similar climates and habitats, and the direct influence of competitors on resource use is investigated by comparisons of species--poor island communities to species-rich mainland ones. Finally, the author discusses those sorts of environments in which the evolution of one species--one resource set is not achieved, and where alternative schemes of resource allocation, often involving several species that act ecologically as one, must be followed.