Herbivores have traditionally been categorized as either dietary generalists or specialists based on what they eat or what they are capable of eating. Shipley and others (2009) argued that specialization should also be based on the limitations imposed on an animal by genetics, physiology, and behavior. They categorized herbivores along a specialist-generalist continuum, with specialists defined as facultative or obligatory, based on seasonal or regional niche breadth. The North American Porcupine (Erethizon dorsatum) has traditionally been considered a generalist herbivore. However, Porcupines often function as dietary specialists consuming a difficult and narrow diet seasonally, regionally, or individually. Porcupines possess physiological and morphological adaptations to consume a difficult diet and do so at a rate higher than other herbivores. Porcupines should therefore be reclassified as facultative specialists. Additional research is required, however, to better understand the degree of specialization exhibited by Porcupines throughout their range. Comparative studies of diet selection across habitats will provide insight into regional and seasonal dietary specialization, and captive studies are required to understand the physiological mechanisms used by Porcupines to consume difficult foods. Documenting inter-population and individual differences in the ability to metabolize plant secondary metabolites will provide insight into the ecology of Porcupines, and will assist in managing potential impacts of Porcupines on native flora as they expand into new habitats.

Bat mortality has been reported at industrial scale wind facilities across North America, with tree-roosting bats accounting for most fatalities, but no data exist for central Canada. We quantified rates of mortality at a wind energy facility in Manitoba, Canada by conducting standardized carcass searches corrected for searcher efficiency and scavenging from mid-August to mid-September 2007. We found that mortality was consistent with, but qualitatively higher than that at comparable wind facilities in western Canada. Mortality of the species most commonly killed, Silver-haired Bats, was evenly distributed across the wind facility, but mortality of Hoary and Eastern Red Bats was higher at some turbines than others.

Several taxa of marine fishes are capable of both aquatic and terrestrial locomotion, yet the terrestrial locomotion mechanics of many of these taxa have not been studied. Many species of the prickleback family Stichaeidae, including the Rock Prickleback, Xiphister mucosus, are capable of both aquatic and terrestrial locomotion. In this study, high-speed video was used to compare the mechanics of aquatic and terrestrial locomotion of X. mucosus. While swimming, tail-beats occur faster, and the velocities of the head and tail are greater than on land. On land, tail-beats are slower and cover a longer distance, yet the distance traveled by the head is similar to the distance traveled during aquatic locomotion. Froude propulsion efficiencies during swimming average 0.75 (s  =  0.05) indicating efficient swimming mechanics in X. mucosus. These efficiency values are typical for other anguilliform swimmers that make terrestrial excursions. Overall, X. mucosus makes slight modifications to its efficient swimming locomotion mechanics, principally by increasing movement of the tail, to move effectively over the terrestrial environment.

Black Bears (Ursus americanus) in southeastern Alaska forage intensively on seed pods and male and female catkins of Black Cottonwood (Populus trichocarpa), often breaking many branches from the trees. We examined the relationship of tree damage to tree size and sex, and to content of selected nutrients in the catkins. Tree damage was related to tree girth: medium-size trees were more heavily damaged than small or large trees, possibly because more branches can easily be reached from a safe perch near the trunk. Overall, female trees were more heavily damaged than males. Foraging intensity was not clearly related to the content of important elements (N, P, K, Ca, C) in catkins and seed pods. Concentrated use of cottonwoods in the study area may occur because high human density offers some protection of small Black Bears from larger bears, and medium-sized cottonwoods are common in this recently deglaciated, early-successional area.