An evaluation of a presence-absence survey to monitor Montezuma quail in western Texas

Developing an effective monitoring program for Montezuma quail (Cyrtonyx montezumae) is a challenge because the technique must be practical for surveying vast landscapes and provide reliable population trends while accounting for its low detectability. I used a presence-absence approach to estimate occupancy (i.e., proportion of sites occupied) and detection probability of Montezuma quail at Elephant Mountain Wildlife Management Area (Elephant Mountain WMA; Brewster County) and the Davis Mountains Preserve (Davis MP; Jeff Davis County) in Texas, July–August 2007 and June–August 2008. In 2008, I also sampled a Del Rio Route (DRR; Val Verde, Terrell, Pecos, and Brewster Counties) and an Uvalde Route (UVR; Uvalde, Real, Edwards, and Val Verde Counties). Four microhabitat (% bare ground, food-plant density, vegetation height, and visual obstruction) and 4 macrohabitat variables (vegetation type, elevation, aspect, and slope) were quantified at each survey point for use in development of resource-selection functions. Microhabitat points could only be sampled at Elephant Mountain WMA and Davis MP because of access. Occupancy rates were high in 2007 (Elephant Mountain WMA [95% CI: 98–100%] and Davis MP [95% CI: 94–100%]). In 2008, occupancy rates for both Elephant Mountain WMA and Davis MP ranged between [95% CI: 37%–48%]. These results indicated that surveys for Montezuma quail have to be repeated multiple times (4–5) in order to ensure at least 90% detection at a point, given a Montezuma quail is present. The survey protocol that was used in this study can help us better understand Montezuma quail populations in west Texas by determining their distribution and allowing us to establish a conservation status for Montezuma quail. Once the distribution of Montezuma quail is determined conducting yearly surveys will allow us to monitor their population distribution.