FORAGING BEHAVIOR OF BROWN BEARS ON KODIAK ISLAND, ALASKA

• Main Author: Deacy, William Welling
• Format: Thesis
• Language: unknown
• Published: University of Montana 2016
• Subjects: Sockeye; Kodiak; Alaska
• Online Access: https://scholarworks.umt.edu/etd/10884; https://scholarworks.umt.edu/context/etd/article/11932/viewcontent/Deacy_umt_0136D_10405.pdf

A key challenge for ecologists is understanding how organisms achieve a positive live history energy balance in spite of resources which vary in abundance across space and through time. Recently, two foraging ecology themes have emerged which contribute to our understanding of this topic. First, resource waves describe how animals can use spatial variation in resource phenology to extend access to foods. Several publications have highlighted animals using resource waves caused by elevational or latitudinal gradients, however, none have demonstrated animals tracking more complex resource waves. Second, the macronutrient optimization hypothesis (MOH) provides a more nuanced model animal diet selection; rather than simply maximizing energy intake, the MOH says animals also attempt to minimize digestive costs by consuming diets with specific mixtures of macronutrients (protein, carbohydrates, and fat). In this dissertation, I used the foraging behavior of Kodiak brown bears in southwest Kodiak Island, Alaska to contribute to these two foraging ecology themes: resource waves and macronutrient optimization. The body of the dissertation consists of four chapters, detailed below. First, to understand how bears respond to sockeye salmon spawning in tributaries, I developed a monitoring method that did not disturb foraging bears, was inexpensive, and could be deployed in remote locations. The system used time-lapse photography and video to observe passing salmon accurately, but at a fraction of the equipment costs and footage review time required by conventional methods. I used these systems to monitor 9-11 streams from 2013-2015. A manuscript detailing this method is currently in review at PeerJ. In southwest Kodiak Island, sockeye salmon spawning phenology varies among different spawning locations, creating a resource wave. While spawning at each of these rivers, lake beaches, and streams may only last for 30-40 days, salmon are spawning somewhere in the study area for over three months. I used data from GPS collared ...