Generalist predators are typically considered to eat foods in proportion to their availability. I show that striped skunks, archtypal generalists, do not just eat foods as available, do not even just select for foods, but switch selection among prey types. In various experiments I showed that skunks do not change prey preference, but they do change preference for where they look for prey, they learn what types of microhabitats prey are found in, they form olfactory search images of prey (OSI), they form these OSI both in the short term and in the long term, both for many small prey items and for few large ones, they form OSI's in relation to what habitat the skunks are searching in, and they change foraging pattern in response to finding different types of foods.
Many other predators use one or other of these mechanisms, but rarely has an animal been shown to use several--I argue that this is because biologists have not looked for many such mechanisms together, and that it is common for generalist predators to switch among prey types. If it is common, then generalist predators should exert density-dependent predation on prey, and should to some extent, regulate prey densities. I discuss various field studies of predator-prey relationships that suggest this. / Graduate
| Identifer | oai:union.ndltd.org:uvic.ca/oai:dspace.library.uvic.ca:1828/9462 |
| Date | 18 June 2018 |
| Creators | Nams, Vilis Ojars |
| Contributors | Gregory, Patrick T. |
| Source Sets | University of Victoria |
| Language | English, English |
| Detected Language | English |
| Type | Thesis |
| Format | application/pdf |
| Rights | Available to the World Wide Web |
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