. The Canadian field-naturalist. 2004 Moore and Kenagy: Consumption of Shrews by Grayling 13. Figure 1. Shrews removed from the stomachs of two Arctic GrayUng, in various stages of digestion. Upper. Shrews from a 522 g Arctic Grayling sampled at Elva Creek (59°34'N, 159°05'W) — Sorex monticolus (UWBM 74152} left and Sorex cinereus (UWBM 74151) right. Lower. Shrews from a 591 g Arctic Grayling at Litde Togiak River (59''36"N, 159°04'W) — Sorex cinereus (UWBM 74155) left, 5. cinereus (UWBM 74154) center, and Sorex monticolus (UWBM 74153) right. cy distributions using the Poisson function in
. The Canadian field-naturalist. 2004 Moore and Kenagy: Consumption of Shrews by Grayling 13. Figure 1. Shrews removed from the stomachs of two Arctic GrayUng, in various stages of digestion. Upper. Shrews from a 522 g Arctic Grayling sampled at Elva Creek (59°34'N, 159°05'W) — Sorex monticolus (UWBM 74152} left and Sorex cinereus (UWBM 74151) right. Lower. Shrews from a 591 g Arctic Grayling at Litde Togiak River (59''36"N, 159°04'W) — Sorex cinereus (UWBM 74155) left, 5. cinereus (UWBM 74154) center, and Sorex monticolus (UWBM 74153) right. cy distributions using the Poisson function in Matlab , assuming an average number of shrews per Arctic Grayling of (5 shrews in 93 Arctic Gray- ling). We encountered fish with either two or three shrews in their stomachs, but no fish with only one shrew. Based on a random expectation for Arctic Gray- Ung consumption, there was a probability of sam- pling an Arctic Grayling with two shrews and only a probability for three shrews. Thus we conclude that Arctic Grayling consumption is not random, and we speculate that this is due to individual differences in either the effectiveness or motivation of individual Arctic Grayling as shrew predators or scavengers. It may also be due to differences in the probability of shrews entering the feeding sites of specific Arctic Grayling. Although Arctic Grayling are typically considered to be speciahsts on aquatic and terrestrial insects (Arm- strong 1986), our observation indicates that some Arctic Grayling are opportunistic feeders, capable of consuming small mammals. Shrews, typically 4 - 8 g (Nagorsen 1996), represent a meal for Arctic Graylings that provides a large amount of energy compared to that of typical individual invertebrate food items. Con- sumption by Arctic Grayling of small mammals, in- cluding shrews, has been reported by several previous authors. Alt (1978*) reported an unspecified small number of shrews in diets of Arctic Grayling in the
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