Department of Zoology
P.O. Box 118525
University of Florida
Gainesville, FL 32611-8525 USA
phone: 352.392.9169
fax: 352.392.3704
Research
I am currently conducting doctoral work at the University of Florida Department of Zoology on the behavioral ecology of partial migrant birds in Bolivia and Argentina. My collaborators are primarily researchers at the Museo de Historia Natural Noel Kempff Mercado in Santa Cruz, Bolivia and the Universidad de Buenos Aires in Argentina.
My research focuses on the behavioral ecology of partial migratory birds; specifically, the consequences of age, sex, habitat use, social status and diet on the presence or absence of migratory behavior. These proximate factors would determine the migratory behavior in a facultative partial migrant, in which the presence or absence of migratory behavior of an individual may change throughout its lifetime. Conversely, in an obligate partial migrant, migratory or non-migratory behavior is conserved throughout its lifetime, such that that individual is likely born a migrant or a residency, purely determined by genetic factors (Figure 1).
Why is South America’s austral system ideal for studying partial migration? First, it hosts the world’s largest set of partial migrants - almost 70% of its species are partially migratory (Stotz et al. 1996) - making it a hotbed for research on the mechanisms governing partial migratory strategies. Second, central South America is largely composed of highly seasonal dry forests (Cerrado and Chaco). Because partial migration is thought to primarily originate out of such seasonal conditions (Alerstam and Enckell 1979), these habitats are the ideal location for the study of partial migration in the Neotropics. These habitats are also one of the planet’s most endangered formations (Gentry 1993), making an understanding of how migratory birds use these habitats and move across them season-to-season imperative to formulating efficient conservation plans for these species.
Once I identify a facultative partial migrant in South America, my question will be: What factors determine which individuals in a population will migrate and which will be resident? For a facultative partial migrant, I would postulate that migratory behavior is primarily influenced by age, which determines social rank in the population, which in turn influences quality of habitat occupied or diet. Thus, one would expect migratory subdominant individuals to be younger and adult dominants to be resident.
This question is important to answer in order to understand the mechanisms determining partial migratory patterns because whether partial migratory strategies operate in a proximate (i.e., demographic) or ultimate (i.e, genetic) framework will to a great extent determine how results on the behavioral ecology of partial migratory strategies can be interpreted. If obligate partial migration defines a population, then migratory condition may be caused by ultimate, historical factors: real time cues are not used; rather, balancing selection between migratory and sedentary individuals has evolved over time (i.e., a balanced genetic polymorphism; see Lundberg 1987). If partial migration is facultative, however, individuals migrate based on proximate cues such as food availability and weather.