Date of Graduation

2002

Document Type

Thesis

Degree Type

MS

Committee Chair

James T. Anderson

Abstract

Double-observer point counts are a new method of inventorying avian fauna that allow detection probabilities to be calculated for each point or species of bird. These detection rates allow estimation of abundances that are more robust than estimates derived from single-observer counts because detection probabilities factor in birds present but not detected. The combined double-observer (DO) technique involves two observers recording data together on a single data sheet. The primary observer dictates the number of each species that is detected while the secondary observer records this information; the secondary observer also notes birds that the primary observer did not detect. The independent double-observer (IO) protocol involves two observers recording data independently on separate data sheets without verbal communication between observers. The efficacy of these two double-observer point count methods was evaluated by comparing detection probabilities and abundance estimates between the two techniques. Other ancillary information such as bird diversity, avian habitat use, and rare bird species also were evaluated from point count data. Point counts were conducted on 137 point locations within the Camp Dawson Collective Training Area (CDCTA), Kingwood, West Virginia. The CDCTA is comprised of three tracts of land: Briery Mountain, the Cantonment Area, and the Pringle Tract. Counts were performed during the 2000 and 2001 breeding seasons from dawn to 1000 hours utilizing both doubleobserver techniques. The DO technique generated significantly higher detection probabilities (P < 0.05) than the IO approach within most habitat types. The IO approach generated higher abundance estimates (P < 0.05), although this likely occurred because lower detection probabilities over inflated bird abundance estimates. Further analyses of point count data revealed six rare bird species on the CDCTA, similar Shannon diversity among Briery Mountain, the Cantonment Area, and the Pringle Tract, and significant abundance differences among tracts for American Crows (Corvus brachyrhynchos), Redeyed Vireos (Vireo olivaceus), American Robins (Turdus migratorius), European Starlings (Sturnus vulgaris), Hooded Warblers (Wilsonia citrina), and Eastern Towhees (Pipilo erythrophthalmus). These results suggest that conducting point counts with the DO technique will result in more accurate point count data because detection probabilities are higher than those computed from the IO approach. Management recommendations based on rare species findings, bird diversity, and habitat use are to minimize human disturbances on areas housing rare species and regions of high bird diversity.

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