Avian nest predation: relationships with landscape characteristics and influences on adult and nestling behavior.

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.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Natural Res & Env Sciences

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2016

Author dc:creator

• Chiavacci, Scott J

Contributors dc:contributor

• Benson, Thomas J.
• Schooley, Robert L.
• Ward, Michael P.
• Brawn, Jeffery D

• 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

Statement dc:rights

• Copyright 2016 Scott Chiavacci

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/90754

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/90754