4 results
Foreword
- Edited by Reinmar Hager, University of Manchester, Clara B. Jones
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- Book:
- Reproductive Skew in Vertebrates
- Published online:
- 02 February 2010
- Print publication:
- 20 August 2009, pp xi-xviii
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Summary
A brief history of skew theory
New ideas in science don't spring out of nowhere; they combine and build from earlier ones. The concept of reproductive skew is no different, and it is nice to have this opportunity to look back, over 30 years ago now, and identify the various sources and give credit where it's due. The story begins in 1974 at the 16th International Ornithological Congress in Canberra, Australia. During that long flight to Australia from Johannesburg, South Africa, the pilot came on the loudspeaker and announced that the United States President Richard Nixon had just resigned in disgrace over the Watergate scandal. Having been in the field in Africa all summer, this was a shocking return to civilization. Ian Rowley had convened the first symposium on cooperative breeding in birds, with himself, Lew Grimes, Glen Woolfenden, and Amotz Zahavi presenting surveys of the cooperatively breeding species in their respective continents (Australia, Africa, the Americas, and Europe) (Grimes 1976, Rowley 1976, Woolfenden 1976, Zahavi 1976). All four speakers noted that the helper-at-the-nest formof cooperative breeding, where offspring remain on the parental territory, delay breeding, and assist with the care of subsequent broods of their parents, was by far the most common one. Cooperative breeding was associated with a variety of habitats and climates, but most were characterized by sedentary residence on territories or fixed home ranges. Habitat saturation was identified by Woolfenden and Zahavi as the primary force favoring prolonged retention of offspring on the parental territory.
15 - Dawn chorus as an interactive communication network
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- By John M. Burt, Cornell Laboratory of Ornithology, Ithaca, USA, Sandra L. Vehrencamp, Cornell Laboratory of Ornithology, Ithaca, USA
- Edited by P. K. McGregor
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- Book:
- Animal Communication Networks
- Published online:
- 06 August 2010
- Print publication:
- 31 March 2005, pp 320-343
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Summary
Introduction
Dawn chorus singing is a striking behaviour pattern, performed by some temperate-zone and tropical songbird species, as well as a few non-passerine and non-avian species. In a typical chorusing songbird species, all territorial males in a neighbourhood synchronously start singing 30 to 90 minutes before sunrise. During the ensuing chorus period, song rate, singing diversity and song complexity reach maximal levels, and often birds do not seem to be interacting with any one particular neighbour (Hultsch & Todt, 1982). Then, as the light level increases around sunrise, this mode of singing usually abruptly ends. Soon after dawn chorus is over, birds begin to forage and patrol their borders, and they switch to courtship singing or dyadic (i.e. paired) counter-singing with nearby neighbours. Post-chorus singing is typically more sporadic and overall song rates tend to be lower and much more variable than they are at dawn chorus (for a review of dawn chorus behaviour, see Staicer et al. (1996)).
Numerous hypotheses have been proposed to explain dawn chorus singing. In an insightful review, Staicer et al. (1996) outlined 12 non-exclusive hypotheses and compared their predictions against the existing empirical evidence across many songbird and non-songbird species. The 12 hypotheses were grouped into three categories: intrinsic, environmental and social. Intrinsic explanations such as circadian cycles of testosterone and self-stimulation are likely proximate mechanisms for dawn singing (Wingfield & Farner, 1993; Goodson, 1998).
11 - Joint laying systems
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- By Sandra L. Vehrencamp, Cornell University, James S. Quinn, McMaster University
- Edited by Walter D. Koenig, University of California, Berkeley, Janis L. Dickinson, University of California, Berkeley
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- Book:
- Ecology and Evolution of Cooperative Breeding in Birds
- Published online:
- 02 December 2009
- Print publication:
- 22 April 2004, pp 177-196
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Summary
Joint nesting is a relatively rare form of cooperative breeding in which two or more breeding group members of the same sex contribute genes to a clutch of eggs and cooperate in the care of young (Brown 1987; Vehrencamp 2000). Traditionally, joint nesting referred to multiple-female clutches. However, with the development of DNA techniques for assigning paternity, a growing number of cooperative species with shared-paternity clutches have been discovered. Joint-female (or communally laying) systems and joint-male (or cooperatively polyandrous) systems exhibit many important differences. Nevertheless, several avian joint-female species are also characterized by the presence of two or more adult males who share paternity to some degree. Here we focus on the diversity of joint-female systems, referring the reader to Chapter 10 and other reviews for discussions of breeding systems with male cobreeding (Faaborg and Patterson 1981; Hartley and Davies 1994; Ligon 1999).
Most joint-female species are non-passerines. By contrast, helper-at-the-nest species, as well as cooperatively polyandrous species, are found among both the passerines and non-passerines. There may be a good explanation for this pattern. Communally laying species all share one important feature: males make a large contribution to incubation and care of the young. In some joint-female species males perform all of the incubation and subsequent care, whereas in others the males perform more than half of the incubation, including nocturnal incubation.
In a survey of the phylogenetic origins of communal-laying species, all were found to arise in taxa with a history of strong male incubation (Vehrencamp 2000).
4 - Cooperative breeding strategies among birds
- Edited by Alan H. Brush, George A. Clark, Jr.
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- Book:
- Perspectives in Ornithology
- Published online:
- 04 August 2010
- Print publication:
- 31 August 1983, pp 93-134
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Summary
The cooperative rearing of young is a topic of considerable interest to both biological and social scientists. Such behavior reaches its extreme development in many eusocial insect societies, where vast numbers of individuals live their entire lives as sterile workers, rearing young but never themselves becoming reproductives (Wilson 1971). Such sterile castes have not yet been reported among vertebrates. However, there are numerous instances in which individuals of vertebrate species (most of them avian) forego breeding for a significant portion of their adult lives and spend such time helping to rear offspring that are not genetically their own.
There are three fundamental questions surrounding the topic of cooperative breeding in animals. First, what role have ecological factors played in promoting the development of such aid-giving societies? Second, how can such seemingly altruistic behavior be explained in terms of natural selection theory? Third, what behavioral tactics will members of such societies adopt to maximize their own fitness when interacting with others?
In this chapter, we will attempt to address each of these three topics. Before doing so, however, it is necessary for us to define our terms. We use “group” to describe any long-lasting association of more than two individuals (Rowley et al. 1979). An “auxiliary” is any mature, nonbreeding member of a reproducing group. It may or may not provide aid in the rearing of young. “Cooperative breeding” refers to any case where more than two birds provide care in the rearing of young.
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