Persistence of Black-Tailed Deer Fecal Pellets in Coastal Habitats

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The persistence of fecal pellets from Columbian black-tailed deer (Odocoileus hemionus columbianus) was determined for 2 levels of 3 environmental factors: moisture, substrate, and canopy. Pellet persistence was least in moist, vegetated forest and greatest in dry, bare cutover. After 1 year, the mean number of pellets remaining in pellet groups on moist sites was between 16 and 48% of the original complement of 50 pellets. On dry sites between 50 and 70% of the pellets were present after 1 year. Similar trends occurred for visibility of pellet groups. After 2 years, 5-25% of the pellet groups were visible at moist, cutover sites, whereas 25-75% of the pellet groups were visible at dry, cutover sites. Rates of change of pellet group visibility indicate that the number of pellet groups counted on uncleared plots represent from 1 to 3 x the number of pellet groups that were deposited the previous year. J. WILDL. MANAGE. 51(1):33-37 Pellet group surveys are an established method for studying ungulate density in North America. There are, however, disagreements about the utility of pellet group counts (Collins and Urness 1981, Leopold et al. 1984). The assumptions made to interpret pellet group data are reviewed by Robinette et al. (1958) and Neff (1968) who evaluated pellet count techniques and offered improvements to statistical design. Assumptions made to interpret pellet counts (Neff 1968) are violated for some conditions, thereby invalidating results. Persistence and visibility of pellet groups are factors affecting counts (Wallmo et al. 1962, Fisch 1979) but are rarely attributed much importance. That pellet groups persist for the duration of the deposition period is commonly assumed. Persistence after the deposition period has been addressed by clearing plots or marking existing pellet groups. Methods developed to minimize the influence of differing persistence or visibility, such as clearing plots, are time consuming and sometimes impractical. Although problems are associated with pellet group counts, their simplicity makes them a desirable technique and ensures their continued use by wildlife managers. Our objectives were to measure pellet persistence and visibility in different habitats. Three factors are important in determining pellet group persistence: moisture, substrate, and canopy cover. Evaluation of the direction and magnitude of effects impos d by these factors on pellet group persistence and visibility should allow more reliable interpretation of past results, extension of present findings, and improved sampling design. The B.C. Fish and Wildl. Branch, Can. For. Products Co. Ltd., Univ. British Columbia, and This content downloaded from 157.55.39.177 on Sat, 19 Nov 2016 04:38:53 UTC All use subject to http://about.jstor.org/terms 34 PELLET PERSISTENCE * Harestad and Bunnell J. Wildl. Manage. 51(1):1987 Natl. Sci. and Eng. Res. Counc. provided support through grants to F. L. Bunnell. Simon Fraser Univ. provided computer support.