title: Should scientists be required to use a model-based solution to adjust for possible distance-based detectability bias?
abstract: The most popular method used to gain an understanding of population trends or of differences in bird abundance among land condition categories is to use information derived from point counts. Unfortunately, various factors can affect one's ability to detect birds, and those factors need to be controlled or accounted for so that any difference in one's index among time periods or locations is an accurate reflection of differences in bird abundance and not differences in detectability. Avian ecologists could use appropriately sized fixed-area surveys to minimize the chance that they might be deceived by distance-based detectability bias, but the current method of choice is to use a modeling approach that allows one to account for distance-based bias by modeling the effects of distance on detectability or occupancy. I challenge the idea that modeling is the best approach to account for distance-based effects on the detectability of birds because the most important distance-based modeling assumptions can never be met. The use of a fixed-area survey method to generate an index of abundance is the simplest way to control for distance-based detectability bias and should not be universally condemned or be the basis for outright rejection in the publication process.
authors.affiliation: Division of Biological Sciences, University of Montana, 32 Campus Drive # 4824, Missoula, MT, 59812, USA.
authors.forename: Richard L
authors.initials: RL
authors.lastname: Hutto
mesh_terms: D063147:Animal Distribution; D000818:Animals; D001717:Birds / Q000502:physiology*; D003198:Computer Simulation; D017753:Ecosystem; D008954:Models, Biological; D011157:Population Dynamics
keywords: detectability; distance; index; inference; occupancy; point count