The relationship of Rio Grande wild turkey distributions to roads

Abstract

Wildlife Society Bulletin 2005, 33(2):745–748 Peer refereed Distance sampling from roads is a common population estimation technique used for many wildlife species (Brennan and Block 1986, DeYoung and Priebe 1987, Borralho et al. 1996, Dahlheim et al. 2000). A critical assumption of the distance sampling technique is that the distribution of animals is not influenced by the transect, but this assumption may be violated if the transect is a road (Burnham et al. 1980, Buckland et al. 2001, Williams et al. 2001). Attraction of target animals to the transect will result in inflated population estimates, and withdrawal from the transect will bias the estimates low (Verner 1985,Thompson et al. 1998, Buckland et al. 2001). Many authors have suggested line transects should not be positioned along roadways unless individuals are randomly distributed across the landscape (Burnham et al. 1980, Buckland et al. 2001, Williams et al. 2001). Male Rio Grande wild turkeys (Meleagris gallopavo intermedia) likely use roads as display sites in south Texas; thus, population surveys using roads should be conducted outside of the breeding season to reduce the probability of wild turkeys being attracted to roads (DeYoung and Priebe 1987). Eastern wild turkeys (M. g. silvestris) in Virginia used areas >450 m from roads more than expected and areas <150 m from roads in proportion to availability (McDougal et al. 1990). In Arizona, male Merriam’s wild turkeys (M. g. merriami) used areas <200 m from roads less than expected (Rogers et al. 1999). However, none of those studies examined the relationship of roads to wild turkey distributions during specific seasons and time periods. Our objectives were to quantify the association of male and female Rio Grande wild turkeys to roads according to season and time of day, and examine the potential biases of using roads as transects for distance sampling. We conducted this research in order to help develop appropriate protocols for distance sampling of Rio Grande wild turkeys from roads.