The Sensory Ecology of Birds

Author(s):  
Graham R. Martin

The natural world contains a huge amount of constantly changing information. Limitations on, and specializations within, sensory systems mean that each species receives only a small part of that information. In essence, information is filtered by sensory systems. Sensory ecology aims to understand the nature and functions of those filters for each species and sensory system. Fluxes of information, and the perceptual challenges posed by different natural environments, are so large that sensory and behavioural specializations have been inevitable. There have been many trade-offs in the evolution of sensory capacities, and trade-offs and complementarity between different sensory capacities within species. Many behavioural tasks may have influenced the evolution of sensory capacities in birds, but the principal drivers have been associated with just two tasksforaging and predator detection. The key task is the control of the position and timing of the approach of the bill towards a target. Other tasks, such as locomotion and reproduction, are achieved within the requirements of foraging and predator detection. Information thatguides behaviours may often be sparse and partial and key behaviours may only be possible because of cognitive abilities which allow adequate interpretation of partial information. Human modifications of natural environments present perceptual challenges that cannot always be met by the information available to particular birds. Mitigations of the negative effects of human intrusions into natural environments must take account of the sensory ecology of the affected species. Effects of environmental changes cannot be understood sufficiently by viewing them through the filters of human sensory systems.

Author(s):  
Graham R. Martin

The natural world contains a huge amount of constantly changing information but specializations within sensory systems mean that each species receives only a small part of that information. Information is filtered by sensory systems. We cannot assume what a bird can detect–it is important to measure its sensory capacities and to quantify the sensory challenges posed for the conduct of tasks in different environments. No sensory system can function adequately throughout the full ranges of stimuli that are found in the natural world. There have been many trade-offs in the evolution of particular sensory capacities and tradeoffs and complementarity between different sensory capacities within a species. Birds may often be guided by information at the limits of their sensory capacities. Information that guides behaviours may often be sparse and partial. Key behaviours may only be possible because of cognitive abilities which allow adequate interpretation of such partial information.


2021 ◽  
Vol 207 (3) ◽  
pp. 303-319
Author(s):  
Heiner Römer

AbstractTo perform adaptive behaviours, animals have to establish a representation of the physical “outside” world. How these representations are created by sensory systems is a central issue in sensory physiology. This review addresses the history of experimental approaches toward ideas about sensory coding, using the relatively simple auditory system of acoustic insects. I will discuss the empirical evidence in support of Barlow’s “efficient coding hypothesis”, which argues that the coding properties of neurons undergo specific adaptations that allow insects to detect biologically important acoustic stimuli. This hypothesis opposes the view that the sensory systems of receivers are biased as a result of their phylogeny, which finally determine whether a sound stimulus elicits a behavioural response. Acoustic signals are often transmitted over considerable distances in complex physical environments with high noise levels, resulting in degradation of the temporal pattern of stimuli, unpredictable attenuation, reduced signal-to-noise levels, and degradation of cues used for sound localisation. Thus, a more naturalistic view of sensory coding must be taken, since the signals as broadcast by signallers are rarely equivalent to the effective stimuli encoded by the sensory system of receivers. The consequences of the environmental conditions for sensory coding are discussed.


Author(s):  
Tatyana O. Sharpee

Sensory systems exist to provide an organism with information about the state of the environment that can be used to guide future actions and decisions. Remarkably, two conceptually simple yet general theorems from information theory can be used to evaluate the performance of any sensory system. One theorem states that there is a minimal amount of energy that an organism has to spend in order to capture a given amount of information about the environment. The second theorem states that the maximum rate with which the organism can acquire resources from the environment, relative to its competitors, is limited by the information this organism collects about the environment, also relative to its competitors. These two theorems provide a scaffold for formulating and testing general principles of sensory coding but leave unanswered many important practical questions of implementation in neural circuits. These implementation questions have guided thinking in entire subfields of sensory neuroscience, and include: What features in the sensory environment should be measured? Given that we make decisions on a variety of time scales, how should one solve trade-offs between making simpler measurements to guide minimal decisions vs. more elaborate sensory systems that have to overcome multiple delays between sensation and action. Once we agree on the types of features that are important to represent, how should they be represented? How should resources be allocated between different stages of processing, and where is the impact of noise most damaging? Finally, one should consider trade-offs between implementing a fixed strategy vs. an adaptive scheme that readjusts resources based on current needs. Where adaptation is considered, under what conditions does it become optimal to switch strategies? Research over the past 60 years has provided answers to almost all of these questions but primarily in early sensory systems. Joining these answers into a comprehensive framework is a challenge that will help us understand who we are and how we can make better use of limited natural resources.


Author(s):  
Gary Totten

This chapter discusses how consumer culture affects the depiction and meaning of the natural world in the work of American realist writers. These writers illuminate the relationship between natural environments and the social expectations of consumer culture and reveal how such expectations transform natural space into what Henri Lefebvre terms “social space” implicated in the processes and power dynamics of production and consumption. The representation of nature as social space in realist works demonstrates the range of consequences such space holds for characters. Such space can both empower and oppress individuals, and rejecting or embracing it can deepen moral resolve, prompt a crisis of self, or result in one’s death. Characters’ attempts to escape social space and consumer culture also provide readers with new strategies for coping with their effects.


Author(s):  
Nicola Green ◽  
Rob Comber ◽  
Sharron Kuznesof

Humans beings in the 21st century face significant social and global change. Ever-evolving digital technologies are increasingly embedded in the material, economic, and socio-cultural milieu; while global crises in climate change present challenges to human and global security and resilience. Social science and human-computer interaction research has investigated how digital systems might help to understand current environmental changes and intervene in the problematic human relationships to scarce resources of the natural world. This chapter reviews research contributions of sustainable human-computer interaction (HCI) and the social sciences on human consumption of resources most crucial to human life: water, energy, and food (WEF). Briefly outlining the current and ongoing evolution of digital technologies particularly concerned with embedded urban digital infrastructures in “smart” and automated technologies and the Internet of Things, it then touches on the scope and scale of the simultaneous environmental challenges posed by population growth and urbanization. It introduces sustainable HCI as one approach that directly addresses both trends. The chapter then outlines the most significant approaches that have informed the development of “sustainable HCI,” and reviews important empirical contributions underpinning the developing interdisciplinary research in the field. It outlines the current understanding of household resource use and considers how developing digital technologies might support domestic resource conservation and mitigate intensive domestically based resource consumption. The chapter closes with observations on the shifting relationships (and sustainable HCI research into them) that might constitute future ways of being in a sustainable digital age.


2021 ◽  
Author(s):  
Ruben Ceulemans ◽  
Laurie Anne Myriam Wojcik ◽  
Ursula Gaedke

Biodiversity decline causes a loss of functional diversity, which threatens ecosystems through a dangerous feedback loop: this loss may hamper ecosystems' ability to buffer environmental changes, leading to further biodiversity losses. In this context, the increasing frequency of climate and human-induced excessive loading of nutrients causes major problems in aquatic systems. Previous studies investigating how functional diversity influences the response of food webs to disturbances have mainly considered systems with at most two functionally diverse trophic levels. Here, we investigate the effects of a nutrient pulse on the resistance, resilience and elasticity of a tritrophic---and thus more realistic---plankton food web model depending on its functional diversity. We compare a non-adaptive food chain with no diversity to a highly diverse food web with three adaptive trophic levels. The species fitness differences are balanced through trade-offs between defense/growth rate for prey and selectivity/half-saturation constant for predators. We showed that the resistance, resilience and elasticity of tritrophic food webs decreased with larger perturbation sizes and depended on the state of the system when the perturbation occured. Importantly, we found that a more diverse food web was generally more resistant, resilient, and elastic. Particularly, functional diversity dampened the probability of a regime shift towards a non-desirable alternative state. In addition, despite the complex influence of the shape and type of the dynamical attractors, the basal-intermediate interaction determined the robustness against a nutrient pulse. This relationship was strongly influenced by the diversity present and the third trophic level. Overall, using a food web model of realistic complexity, this study confirms the destructive potential of the positive feedback loop between biodiversity loss and robustness, by uncovering mechanisms leading to a decrease in resistance, resilience and elasticity as functional diversity declines.


2021 ◽  
Vol 9 ◽  
Author(s):  
Theodora Fuss

The idea of “smart is sexy,” meaning superior cognition provides competitive benefits in mate choice and, therefore, evolutionary advantages in terms of reproductive fitness, is both exciting and captivating. Cognitively flexible individuals perceive and adapt more dynamically to (unpredictable) environmental changes. The sex roles that females and males adopt within their populations can vary greatly in response to the prevalent mating system. Based on how cognition determines these grossly divergent sex roles, different selection pressures could possibly shape the (progressive) evolution of cognitive abilities, suggesting the potential to induce sexual dimorphisms in superior cognitive abilities. Associations between an individual’s mating success, sexual traits and its cognitive abilities have been found consistently across vertebrate species and taxa, providing evidence that sexual selection may well shape the supporting cognitive prerequisites. Yet, while superior cognitive abilities provide benefits such as higher feeding success, improved antipredator behavior, or more favorable mate choice, they also claim costs such as higher energy levels and metabolic rates, which in turn may reduce fecundity, growth, or immune response. There is compelling evidence in a variety of vertebrate taxa that females appear to prefer skilled problem-solver males, i.e., they prefer those that appear to have better cognitive abilities. Consequently, cognition is also likely to have substantial effects on sexual selection processes. How the choosing sex assesses the cognitive abilities of potential mates has not been explored conclusively yet. Do cognitive skills guide an individual’s mate choice and does learning change an individual’s mate choice decisions? How and to which extent do individuals use their own cognitive skills to assess those of their conspecifics when choosing a mate? How does an individual’s role within a mating system influence the choice of the choosing sex in this context? Drawing on several examples from the vertebrate world, this review aims to elucidate various aspects associated with cognitive sex differences, the different roles of males and females in social and sexual interactions, and the potential influence of cognition on mate choice decisions. Finally, future perspectives aim to identify ways to answer the central question of how the triad of sex, cognition, and mate choice interacts.


2021 ◽  
Vol 9 ◽  
Author(s):  
Eliezer Gurarie ◽  
Sriya Potluri ◽  
George Christopher Cosner ◽  
Robert Stephen Cantrell ◽  
William F. Fagan

Seasonal migrations are a widespread and broadly successful strategy for animals to exploit periodic and localized resources over large spatial scales. It remains an open and largely case-specific question whether long-distance migrations are resilient to environmental disruptions. High levels of mobility suggest an ability to shift ranges that can confer resilience. On the other hand, a conservative, hard-wired commitment to a risky behavior can be costly if conditions change. Mechanisms that contribute to migration include identification and responsiveness to resources, sociality, and cognitive processes such as spatial memory and learning. Our goal was to explore the extent to which these factors interact not only to maintain a migratory behavior but also to provide resilience against environmental changes. We develop a diffusion-advection model of animal movement in which an endogenous migratory behavior is modified by recent experiences via a memory process, and animals have a social swarming-like behavior over a range of spatial scales. We found that this relatively simple framework was able to adapt to a stable, seasonal resource dynamic under a broad range of parameter values. Furthermore, the model was able to acquire an adaptive migration behavior with time. However, the resilience of the process depended on all the parameters under consideration, with many complex trade-offs. For example, the spatial scale of sociality needed to be large enough to capture changes in the resource, but not so large that the acquired collective information was overly diluted. A long-term reference memory was important for hedging against a highly stochastic process, but a higher weighting of more recent memory was needed for adapting to directional changes in resource phenology. Our model provides a general and versatile framework for exploring the interaction of memory, movement, social and resource dynamics, even as environmental conditions globally are undergoing rapid change.


2011 ◽  
Vol 83 (4) ◽  
pp. 1345-1358 ◽  
Author(s):  
Gisele R. Winck ◽  
Tiago G. Dos Santos ◽  
Sonia Z. Cechin

The increasing human occupation of natural environments is one of the greatest threats to biodiversity. To mitigate the negative anthropogenic effects, it is necessary to understand the characteristics of natural populations and the natural history of species. A study was conducted with an assemblage of lizards from a disturbed area of the Pampa biome, from February 2001 to January 2004. The assemblage showed a unimodal seasonal pattern, with the recruitment period occurring during the warmer months. The captures were seasonal for two of the three monitored years, and concentrated within warmer months. The minimum temperature explained the number of catches for the assemblage as a whole. However, when the species were analyzed individually, the temperature only explained the seasonal occurrence of Teius oculatus. The abundance of species was significantly different in the third year of study for Cercosaura schreibersii and Ophiodes striatus. This latter species was no longer registered in the study area from May 2003 until the end of the study. Therefore, O. striatus may be more sensitive to environmental changes, considering the events of change in vegetation during the study. With frequent and increasing environmental disturbances, it is necessary to take conservation measures and encourage the increase of knowledge on Pampean lizards.


Human health depends on nature. This is a basic statement on which the fundaments of this book rest. Functional and diverse ecosystems, from which we derive fresh air and water, soil to grow food, timber to build houses, settings for play and recreation, are a prerequisite for human health and survival. The latest centuries’ unprecedented speed in societal and environmental changes has come to threaten the health of natural environments and by this threatening our own health. While we cannot, and should not, reverse the trend of sound development, we need to find better and healthier ways to interact with nature—in urban as well as in non-urban areas. This chapter will give a background to this book’s development and put the topic of nature and public health into a broad, outreaching context. It also presents an overview of the book’s full content, giving a brief description of each chapter.


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