Date Thesis Awarded
Honors Thesis -- Access Restricted On-Campus Only
Bachelors of Science (BS)
Daniel A. Cristol
Occupancy modeling is a common method for analyzing point-count data when the probability of detecting a species is less than one. Occupancy studies entail visiting sites multiple times during a primary sampling period. The resulting detection histories are used to estimate a probability of detection (p) and the probability of occupancy (Ψ). Sites may be visited consecutively on a single day or separately over multiple days within a breeding season. Single-day visits cost less time and money and may be less likely to violate the closure assumptions of occupancy modeling. However, the single-day design may not capture the spectrum of environmental conditions captured in multiple-day surveys, which could result in lower detection probabilities. This study compared detection probabilities and occupancy probabilities for bird populations that were surveyed with both a single-day and a multiple-day sampling design. Sixty-two (62) species were detected on 131 point-count locations throughout the breeding season (28 May to 28 June 2012), of which 33 had sufficient sample size for analysis. Estimates of detection probabilities were consistently lower and occupancy estimates consistently higher in the multiple-day sampling design compared to the single-day design. When planning future occupancy studies, the trade-off between detection and occupancy probabilities, as well as factors such as song rate and the home-range size of the species of interest, need to be accounted for.
Watson, Kelly, "A comparison of single-day versus multiple-day sampling designs using occupancy modeling" (2013). Undergraduate Honors Theses. William & Mary. Paper 645.
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