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Title:Avian nest predation: relationships with landscape characteristics and influences on adult and nestling behavior.
Author(s):Chiavacci, Scott J
Director of Research:Benson, Thomas J.
Doctoral Committee Chair(s):Schooley, Robert L.
Doctoral Committee Member(s):Ward, Michael P.; Brawn, Jeffery D
Department / Program:Natural Res & Env Sci
Discipline:Natural Res & Env Sciences
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):nest survival
nest success
nest predator
avian ecology
nest defense
landscape ecology
predator-prey dynamics
time-lapse video
nest camera
shrubland bird
nest site
fledging behavior
Abstract:Nest predation is the leading cause of reproductive failure in birds. As a result, many studies have sought to understand what factors influence nest predation as well as the ways in which birds respond to predation. However, identifying the factors that lead to variation in nest predation has proven challenging, due to the diversity of nest predators involved and the often ignored fact that different predators interact with habitat attributes at different spatial scales. Furthermore, although studies continue to reveal the impact that both direct predation and perceived predation risk have on birds, gaps remain in our understanding of how birds respond behaviorally to information regarding predation risk. My research sought to address the following: (1) is the relationship between predator-specific nest predation and landscape composition dependent on the spatial scale at which it is examined, (2) are the nest defense behaviors of parent birds influenced by public information regarding nest predation risk, and (3) does nest predation risk influence the timing of nest departure in nestling birds. Regarding my first question, I found that predation by different predator species was influenced by different land cover types surrounding nests, but the direction and strength of relationships often varied among scales and predators. In general, composition at larger scales appeared to more strongly influence predation probability than that at smaller scales. Regarding my second question, I discovered that nest defense behaviors of parent birds were influenced by public information regarding predation risk, the use of public information depended on the life history traits of birds, and that heterospecific, but not conspecific public information was used. Regarding my third question, I found that when nestlings occupied high predation risk nest sites, they fledged earlier in the day and all broodmates within a nest fledged over a shorter period of time. My results illustrate that understanding the impact of landscape composition on predation by different predators requires evaluating patterns at multiple landscape scales. In doing so, we are likely to improve our ability to ascertain the mechanisms leading to variation in nest predation. In addition, although the importance of PI during habitat selection and settlement behaviors in birds is widely recognized, my results reveal birds use PI in other contexts as well, suggesting an avenue for further research into the role PI plays in shaping bird behavior. Lastly, my finding that predation risk impacted the timing of fledging suggests that by fledging earlier and more quickly, young in high risk nests presumably decreased their chances of being depredated in the nest, while those occupying safer nests are likely under reduced pressure to fledge as early as possible. This outcome indicates nestlings preparing to fledge likely face more complex situations than currently understood and the timing of nest departure is an important decision made in an effort to maximize fledgling fitness.
Issue Date:2016-04-18
Rights Information:Copyright 2016 Scott Chiavacci
Date Available in IDEALS:2016-07-07
Date Deposited:2016-05

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