• Login
    View Item 
    •   Home
    • University of Alaska Fairbanks
    • UAF Graduate School
    • Biological Sciences
    • View Item
    •   Home
    • University of Alaska Fairbanks
    • UAF Graduate School
    • Biological Sciences
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Browse

    All of Scholarworks@UACommunitiesPublication DateAuthorsTitlesSubjectsTypeThis CollectionPublication DateAuthorsTitlesSubjectsType

    My Account

    Login

    First Time Submitters, Register Here

    Register

    Statistics

    Display statistics

    Physiological adaptations for overwintering by the black-capped chickadee (Parus atricapillus) in interior Alaska (64 degrees North latitude)

    • CSV
    • RefMan
    • EndNote
    • BibTex
    • RefWorks
    Thumbnail
    Name:
    Sharbaugh_S_1997.pdf
    Size:
    2.523Mb
    Format:
    PDF
    Download
    Author
    Sharbaugh, Susan Marie
    Keyword
    Zoology
    Animal Physiology
    Ecology
    Metadata
    Show full item record
    URI
    http://hdl.handle.net/11122/9504
    Abstract
    Winter in interior Alaska (64$\sp\circ$N) is characterized by short photoperiod (LD 5:19) and chronic subfreezing temperatures. These conditions present a physiological challenge to overwintering animals. This challenge increases as body size decreases. In small animals, higher surface to volume ratio and concomitant higher mass-specific metabolic rate (compared to larger animals) vastly increase energetic demand. This thesis focuses on the physiological adaptations of the smallest (12 g) overwintering bird in interior Alaska, the Black-capped Chickadee (Parus atricapillus). To determine if seasonal acclimatization of Black-capped Chickadees at high latitude differs from that of conspecifics at lower latitudes, standard metabolic rates (SMR), metabolic response to low temperature (${-}30\sp\circ$C), use of nocturnal hypothermia, body mass, fat reserves, and conductance were measured over two winters and one summer in three groups of seasonally acclimatized captive birds. Body mass and conductance did not vary with season, but furcular fat levels were higher in winter. Birds used nocturnal hypothermia when exposed to ${-}30\sp\circ$C in summer or winter. Although SMR did not vary seasonally, winter SMRs differed between the two winters studied. Nocturnal hypothermia in summer and decreased SMR during winter have not been reported in conspecifics at lower latitudes. Lipid reserves play an important role in fueling the energy demands of overwintering birds. Black-capped Chickadees exhibit a daily and seasonal cycle of fattening. At high latitudes (64$\sp\circ$N), fat to fuel an 18 hour nocturnal fast is deposited during 6 hours of daylight available for foraging. Daily fattening rates are highest in December when ambient conditions are most limiting. Activity of the fat deposition-promoting enzyme, adipose lipoprotein lipase (ALPL), was measured in furcular fat samples from seasonally acclimatized captive birds to determine its role in daily and seasonal fattening cycles. ALPL activity levels were 20-30 times higher than those previously reported for passerines. Seasonal variation in enzyme activity positively correlated with changes in fattening rates from December to April. Alaskan birds displayed the highest level of activity when compared to conspecifics at lower latitudes. All subpopulations measured exhibited activity higher than previously reported for small birds.
    Description
    Dissertation (Ph.D.) University of Alaska Fairbanks, 1997
    Date
    1997
    Type
    Dissertation
    Collections
    Biological Sciences

    entitlement

     
    ABOUT US|HELP|BROWSE|ADVANCED SEARCH

    The University of Alaska Fairbanks is an affirmative action/equal opportunity employer and educational institution and is a part of the University of Alaska system.

    ©UAF 2013 - 2023 | Questions? ua-scholarworks@alaska.edu | Last modified: September 25, 2019

    Open Repository is a service operated by 
    Atmire NV
     

    Export search results

    The export option will allow you to export the current search results of the entered query to a file. Different formats are available for download. To export the items, click on the button corresponding with the preferred download format.

    By default, clicking on the export buttons will result in a download of the allowed maximum amount of items.

    To select a subset of the search results, click "Selective Export" button and make a selection of the items you want to export. The amount of items that can be exported at once is similarly restricted as the full export.

    After making a selection, click one of the export format buttons. The amount of items that will be exported is indicated in the bubble next to export format.