Wild turkeys in the urban matrix: how an introduced species survives-and thrives-in a multifunctional landscape

Abstract

An understanding of how species responds to urbanization is important for conservation and management of possible human-wildlife conflicts. Wild turkeys (Meleagris gallopavo) have recently successfully entered many urban landscapes, however their apparent success remain poorly understood. Most studies of wild turkeys have occurred in forested or agricultural landscapes. I estimated several important demographic, home range, and habitat use behaviors for wild turkey in areas of varying degrees of urbanization in the Minneapolis-St. Paul, Minnesota, USA, metropolitan area. My research objectives centered on providing the first information on urban wild turkey ecology, including: 1) assessing urban wild turkey nesting behavior and possible changes to reproductive measures, 2) investigation of urban wild turkey survival and the influence of local mortality agents, and 3) assessing urban wild turkey home range characteristics and habitat use.I captured and equipped 60 female wild turkeys with back-pack style VHF radio transmitters during 2010-2013. Monitored female wild turkey reproductive measures and nest survival were remarkably similar both among my study areas and previous rural wild turkey research. For all monitored females across all study areas and years, first nesting rate was 73.7% (n = 57), average date of onset of incubation was 2 May (n = 42), and hatch rate was 84% (n = 26). For all monitored females across all study areas and years mean clutch size was 10.2 (n = 42), and differed by study area (÷2 = 8.30, DF = 2, P = 0.02). For all monitored females across all study areas and years nest survival rate was 0.56 (n = 42). Monitored nests tended to have high visual concealment at the nest bowl, with a strong trend for habitat variables related to vegetative density and height at the nest bowl scale, and distance to open water on the greater landscape.Across all study areas and all female wild turkeys in 2010-2013 the annual survival rate was 0.43 (CI = 0.32 - 0.58; n = 55). Across all study areas and all female wild turkeys in 2010-2013, seasonal survival rates were as follows: 1) spring survival rate was 0.61 (CI = 0.50 - 0.75; n = 55); 2) summer survival rate was 0.83 (CI = 0.71 - 0.96; n = 34); 3) autumn survival rate was 0.89 (CI = 0.75 - 0.99; n = 28); and 4) winter survival rate of 0.96 (CI = 0.89 - 1.0; n = 25). During the brooding seasons of 2010 through 2012, an estimated 216 poults successfully hatched. Combined poult survival rate to 2 weeks post-hatch was 0.35, declining to 0.26 4-weeks post-hatch. Overall, mammalian and avian predation accounted for 63.3% of all observed female mortalities, followed by vehicle strikes (23.3%), harvest (3.3%), and unknown causes (10.0%). Predation remained the leading cause of mortality regardless of age-class, although predation tended to be higher in female adults (61.5%) than juveniles (47.1%).Across all study areas and all female wild turkeys, average annual home range size was 41.3 ha (n = 28). Annual home range size for suburban females (64.5 ha, n = 9) was larger than rural (38.0 ha, n = 11) or urban females (19.6 ha, n = 8), with home range size differing between study areas (÷2 = 12.26, DF = 2, P = 0.002). Spring/summer home ranges included both females that attempted to nest, brooding hens, and non-reproductively active females. Across all study areas and all female wild turkeys, average spring/summer home range size was 26.4 ha (n =37). Spring/summer home range size for suburban (44.8 ha, n = 11), rural (23.0 ha, n = 17), and urban females (10.3 ha, n = 9) did not differ. Across all study areas and all female wild turkeys average autumn/winter home range size was 25.1 ha (n = 28). Autumn/winter home range size for suburban (30.9 ha, n = 9), rural (28.6 ha, n = 11), and urban females (13.8 ha, n = 8) did not differ.Habitat use by wild turkey populations in urban settings relied heavily on `natural-like' habitat, as well as on developed, human-dominated areas. For this study `natural-like' habitat (i.e., parkland, conifer tree) was predictive of spring/summer habitat use and developed habitat (i.e., residential areas, agricultural) was predictive of autumn/winter habitat use. These range shifts are likely linked to resource availability and specific habitat availability (i.e., nesting and brood habitats).