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Understanding physiological and behavioral mechanisms underlying the diversity of observed life-history strategies is challenging because of difficulties in obtaining long-term measures of fitness and in relating fitness to these mechanisms. We evaluated effects of experimentally elevated testosterone on male fitness in a population of dark-eyed juncos(More)
Concentrations of gonadal steroids such as testosterone (T) often vary widely in natural populations, but the causes and particularly the consistency of this variation is relatively unexplored. In breeding males of a wild population of the dark-eyed junco (Junco hyemalis), we investigated seasonal and individual variation in circulating T during two(More)
1. Despite considerable recent interest in plasma and yolk testosterone (T) in female birds, relatively little is known about environmental regulation of female T, individual variation in female T or the relationship between plasma and yolk T. 2. In breeding females of a wild population of dark-eyed junco (Junco hyemalis), we assessed variation in the(More)
To explore whether selection for testosterone-mediated traits in males might be constrained by costs of higher testosterone to females, we examined the effects of experimental elevation of plasma testosterone on physiological, reproductive, and behavioral parameters in a female songbird, the dark-eyed junco (Junco hyemalis). We used subcutaneous implants to(More)
Resource pulses can have cascading effects on the dynamics of multiple trophic levels. Acorn mast is a pulsed resource in oak-dominated forests that has significant direct effects on acorn predators and indirect effects on their predators, prey, and pathogens. We evaluated changes in acorn mast, rodent abundance, raptor abundance, and reproductive success(More)
Because of their role in mediating life-history trade-offs, hormones are expected to be strongly associated with components of fitness; however, few studies have examined how natural selection acts on hormonal variation in the wild. In a songbird, the dark-eyed junco (Junco hyemalis), field experiments have shown that exogenous testosterone alters(More)
Introduction Birds vary both inter-and intra-specifically in their phenotypes in ways that appear adaptive, and some of this variation is mediated by hormones. The challenge is to account for how and why such variation arises, both mechanistically and in terms of evolutionary forces. In this paper we outline some of the contributions to be expected from a(More)
Library instruction plays a key role in web usability. During instructional sessions, librarians shape the ways students behave on the library website (user's web behavior). They teach students how to use the library website and demonstrate various pathways by which students can access library resources and services. Although library instruction and user's(More)
This case study of a data curation project, which is currently in progress, demonstrates how a team of scientists has worked, in partnership with librarians, to plan to preserve their scientific output in an institutional repository. In addition, this case study offers a unique perspective. The author worked as one of the scientists in this particular(More)
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