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Contributed Poster

Session: Physiological Ecology

PS 15-214 - CANCELLED - Causes and consequences of Life History Stage overlap: Insights from migratory songbirds

Monday, August 7, 2023
5:00 PM – 6:30 PM PDT
Location: ESA Exhibit Hall

    Presenting Author(s)

  • FN

    Frederick A. Nelson

    Graduate Student
    University of California, Davis
    Davis, California, United States

    • Coauthor(s)

  • TC

    Thomas Coombs-Hahn

    Professor and PI in the Dept of Neurobiology, Physiology and Behavior
    University of California, Davis
    Davis, United States

Abstract: The concept of life-history stages (LHSs) refers to a set of correlated morphological, physiological, and behavioral traits related to a specific process, typically around a particular time of year. LHSs present a ubiquitous ability of animals to expand their geographic range and optimize their fitness across different habitats, and/or across temporally changing conditions (e.g., seasonality). One of the main drivers of the evolution of distinct, non-overlapping LHSs is thought to be a mechanism for avoiding simultaneous expression of multiple highly demanding processes, and related nutritional, energetic, and time conflicts that would lead to reduced fitness. Because transitions between these stages cannot occur instantly, some level of overlap between adjacent stages is inevitable as one stage goes through termination and the next goes through preparation. However, there also is substantial inter-individual and inter-species variation in the extent to which LHSs overlap. As part of my study of LHS coordination in migratory white-crowned sparrows (Zonotrichia leucophrys oriantha and Z. l. gambelii), I present a conceptual framework for understanding both the causes and consequences of LHS overlap, as well as the implications for individuals’ and species’ responses to timing challenges presented by climate change. I emphasize transitions between reproduction, plumage molt, and preparation for migration in these two long-distance migratory subspecies, and whether individuals overlap stages because they can or because they must.