xi, 51 p. : ill. (some col.) / Conducting field studies for human centric research often demands a significant amount of time and effort. Virtual Environments (VE) can be a potential alternative to reduce such requirements and help scale the field studies. However, we may experience a performance difference between (1) a virtual trial, and (2) a field trial of the same study. To learn under what circumstances a VE can successfully replace a field study and when it fails, this thesis describes a route-following experiment that compares the participants' performance between a simple VE and a field setup. The experiment results unveil that there is a significant difference in performance between a physical and a virtual setup for more challenging navigational tasks, whereas no significant difference is observed for simpler tasks. This finding encourages us to replace a less challenging field study with a simple VE, and explore the possibilities for a complex one. / Committee in charge: Dr. Stephen Fickas, Chairperson; Dr. Christopher Wilson, Member

Central place foragers, such as territorial hummingbirds, feed from resources that tend to be constant in space and to replenish with time (e.g. nectar in flowers). The ability to remember both where and when resources are available would allow these animals to forage efficiently. Animals that feed at multiple locations would also benefit from forming routes between these multiple locations. Hummingbirds are thought to forage by repeating the order in which they visit several locations following a route called a “trapline”, although there are no quantitative data describing this behaviour. As a first step to determining how and if wild free living hummingbirds forage by traplining, I decomposed this behaviour into some of its key components. Through five field experiments, where I trained free-living hummingbirds to feed from artificial flowers, I confirmed that territorial hummingbirds will, in fact, trapline. Birds will use the shortest routes to visit several locations and will prioritize those locations that are closest to a usual feeding site. Additionally, even though hummingbirds can learn to use temporal information when visiting several patches of flowers, the spatial location of those patches has a larger influence in how these birds forage in the wild. Since male and female hummingbirds were thought to forage differently I also tested whether there were sex differences in the types of cues they use when foraging. Contrary to expectation, female hummingbirds will also use spatial cues to relocate a rewarded site. Using the foraging ecology of rufous hummingbirds to formulate predictions as to what information these birds should use has lead me to discover that these birds forage in a completely different way than previously thought.