Estimating sika deer abundance using camera surveys
Date
2010
Authors
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Publisher
University of Delaware
Abstract
Camera surveys are an accepted tool for estimating wildlife abundance and occupancy and have been used throughout the world. Camera surveys tend to be less invasive, less costly, and more accurate than other means in certain situations. I sought to expand and test the effectiveness of camera surveys during July and August of 2008 and 2009 for sika deer at Tudor Farm, LLC in Dorchester County, Maryland. In 2008, I setup surveys with a 7-day pre-bait period followed by a 7-day active camera survey with 15 cameras. In 2009, I changed the camera survey setup to account for any bias that may have occurred due to using the same camera sites for consecutive surveys. I also set camera surveys to run for the entire 14-day survey period to determine optimum survey length. Camera density for both years was 1 camera per 65-ha. The estimates generated by the Jacobson method and Bowden’s estimator were similar between years. In 2009, increasing photo intervals from 1- minute to 5 and 10-minute intervals reduced the number of pictures by 66% and 81% while providing similar population estimates. I calculated the daily detection probabilities for all identifiable deer and I used radio-collared males that occurred within 2-km of the survey grid to assist in determining the optimum survey length. Detection probability did not vary between surveys in the same year, but varied between 2008 and 2009, most likely as a result of greater amounts of bait being available in 2008. Camera surveys have proven to be an accurate and effective means of estimating sika deer abundance and could be expanded to the entire population of Maryland.