Issues in the classification of multimodal communication signals.

Communication involves complex behavior in multiple sensory channels, or "modalities." We provide an overview of multimodal communication and its costs and benefits, place examples of signals and displays from an array of taxa, sensory systems, and functions into our signal classification system, and consider issues surrounding the categorization of multimodal signals. The broadest level of classification is between signals with redundant and nonredundant components, with finer distinctions in each category.

Predation: Prey plumage adaptation against falcon attack.

Several plumage types are found in feral pigeons (Columba livia), but one type imparts a clear survival advantage during attacks by the swiftest of all predators--the peregrine falcon (Falco peregrinus). Here we use quantitative field observations and experiments to demonstrate both the selective nature of the falcon's choice of prey and the effect of plumage coloration on the survival of feral pigeons. This plumage colour is an independently heritable trait that is likely to be an antipredator adaptation against high-speed attacks in open air space.

Ethology and the origins of behavioral endocrinology.

The neurosciences embrace many disciplines, some long established, others of more recent origin. Behavioral endocrinology has only recently been fully acknowledged as a branch of neuroscience, distinctive for the determination of some of its exponents to remain integrative in the face of the many pressures towards reductionism that so dominate modern biology. One of its most characteristic features is a commitment to research at the whole-animal level on the physiological basis of complex behaviors, with a particular but by no means exclusive focus on reproductive behavior in all its aspects.

Do responses of galliform birds vary adaptively with predator size?

Past studies of galliform anti-predator behavior show that they discriminate between aerial and ground predators, producing distinctive, functionally referential vocalizations to each class. Within the category of aerial predators, however, studies using overhead models, video images and observations of natural encounters with birds of prey report little evidence that galliforms discriminate between different raptor species. This pattern suggests that the aerial alarm response may be triggered by general features of objects moving in the air.

Bird calls: their potential for behavioral neurobiology.

Birdsongs are always part of larger set of sound signals. Every bird uses a repertoire of calls for communication. Calls are shorter and simpler than songs, with a much larger range of functions.

Innateness and the instinct to learn.

Concepts of innateness were at the heart of Darwin's approach to behavior and central to the ethological theorizing of Lorenz and, at least to start with, of Tinbergen. Then Tinbergen did an about face, and for some twenty years the term 'innate' became highly suspect. He attributed the change to Lehrman's famous 1953 critique in which he asserted that classifying behaviors as innate tells us nothing about how they develop.

The Umwelt and its relevance to animal communication: introduction to special issue.

This introduction applies J. von Uexküll's (1934/1957) concept of the Umwelt to the study of animal communication, particularly as it pertains to studies presented at a recent workshop on animal communication in the context of the environment. The environment is conceived broadly in the articles that follow, including the many physical and social environments in which an animal may find itself.

Dialects in wild chimpanzees?

Chimpanzees emit a loud, species-typical long distance call known as the pant hoot. Geographic variation between the pant hoots of chimpanzees living in two neighboring populations, the Mahale Mountains and Gombe Stream National Parks, Tanzania, was examined. Analysis of six acoustic features revealed subtle differences in the way chimpanzees from the two populations called.