Kathi L. Borgmann
I am a PhD student in Dr. Conway’s Lab. Broadly speaking, my research
interests center on avian ecology and conservation, mechanisms underlying nest
predation in songbirds, plant-animal interactions, and life-history traits in birds.
I received my undergraduate degree in Biological Aspects of Conservation from
the University of Wisconsin at Madison in 1998. I received my Masters degree from The
Ohio State University in 2002. My thesis focused on interactions between non-native
plants and avian nesting success. Specifically, I examined the effects of urbanization on
the probability of invasion by non-native plants in forest patches and, in turn, how nonnative plants influence nesting success of forest songbirds. My results suggested that the
proportion of urban land cover surrounding forest patches influenced the percent cover of
honeysuckle (Lonicera spp.) within the understory of forest patches (Borgmann and
Rodewald 2005). My research illustrated how consideration of factors at the scale of the
entire landscape can substantially improve conservation outcomes in both restoration
efforts and reserve-design planning. Results from my Masters research also suggested
that non-native plants negatively affect nesting success of songbirds (Borgmann and
Rodewald 2004), but the mechanisms and evolutionary consequences require further
study.
My PhD research centers on investigating why nesting success of songbirds varies
throughout a breeding season: implications on breeding phenology and variation in lifehistory traits. Nesting success of Wilson’s Warblers and Dusky Flycatchers increases
throughout the breeding season, such that birds initiating nests early in the breeding
season have a lower probability of fledging offspring. Seasonal increases in nesting
success contradict the presumed benefits gained by laying larger clutches early in the
season. This pattern creates a dilemma for single-brooded passerines with limited
renesting frequency. To maximize clutch size individuals should breed early; however,
breeding early incurs a higher risk of predation. Alternatively, breeding later in the
season reduces the maximum number of young but increases probability of success.
Therefore decisions on when to breed may be influenced by seasonal patterns of nesting
success; however, no study to my knowledge has empirically examined factors that
influence seasonal patterns of nesting success and subsequently affect breeding
phenology. I am testing three hypotheses to explain why nesting success varies
throughout the season: due to seasonal changes in (1) nest concealment, (2) alternative
prey for nest predators, or (3) abundance of nest predators. Understanding factors that
influence variation in nesting success will have implications for the evolution of breeding
date and variation in life-history traits. Examining seasonal variation also will help
isolate factors that limit nesting success.
Publications
Borgmann, K. L., and A. D. Rodewald. 2005. Forest restoration in urbanizing
landscapes: interactions between land uses and an exotic shrub. Restoration
Ecology 13:334-340.
Borgmann, K. L., and A. D. Rodewald. 2004. Nest predation in an urbanizing
landscape: the role of exotic shrubs. Ecological Applications 14:1757-1765.
Borgmann, K. L., S. F. Pearson, D. J. Levey, and C. H. Greenberg. 2004. Wintering
Yellow-rumped Warblers (Dendroica coronata) track manipulated abundance of
Myrica cerifera fruits. Auk 121:74-87.
Borgmann, K. L., D. M. Waller, and T. P. Rooney. 1999. Does balsam fir (Abies
balsamea) facilitate the recruitment of eastern hemlock (Tsuga canadensis)?
American Midland Naturalist 141:391-397.