Habitat use, movement and survival of Merriam's turkeys in the Jemez Mountains, New Mexico
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Merriam’s turkeys (Meleagris gallopavo merriami) are historically found in conjunction with ponderosa pine (Pinus ponderosa), Gambel oak (Quercus gambelii), and piñon-juniper (Pinus edulis, Juniperus spp.) habitats in the southwest United States. We initiated this study on the Valles Caldera National Preserve in northern New Mexico in preparation for management practices such as public access and use and landscape restoration including forest thinning and prescribed fire which have the potential to greatly alter these habitats. We captured, radio-marked and monitored the habitat use and movements of 49 turkeys during a 3 year period (2008-2011) in the Jemez Mountains of northern New Mexico. We used radio-telemetry to identify 110 turkey roost sites: 60 winter, 28 summer, 16 year-round, and 6 brood Roost sites accounted for >2100 roost trees. Summer roost sites were predominantly located on northwest aspects (61.5%) and consisted primarily of Douglas-fir trees (Pseudotsuga menziesii) (92.7%). Year-round and winter roost sites were primarily located on south and southeast aspects respectively (62.5% and 68.2%). Ponderosa pine was the dominant tree used for both year-round and winter roosting (84.5% and 96.6% respectively). We used logistic regression to explain the difference between randomly selected winter roost sites (n=30) and randomly selected stand inventory plots (n=30). Winter roost sites averaged 29 roost trees per site. Roost trees had larger diameter (58cm, SE= 3cm) and were taller (22m, SE=.6m) than comparison trees. Roost sites had lower tree density (398trees/ha, SE=57trees/ha) and basal area (27m2/ha, SE=2m2/ha) and higher percent canopy closure (73%, SE=2%) than comparison plots. We validated our top model using additional turkey roost sites (n=24) and an additional set of randomly selected stand inventory plots (n=24). Our model correctly confirmed 100% of turkey roost sites and correctly rejected 100% of stand inventory plots. Resource managers should maintain patches of large-diameter, >20m tall ponderosa pine trees for turkey roosts. In areas where large trees have been replaced by even-aged small trees thinning should occur to encourage tree growth. We used 97 roost sites that included >1900 trees to calculate daily movements and documented 303 diurnal use sites. Turkeys selected habitat < 500 m from roost sites for diurnal use activities throughout all seasons. Winter activities were further concentrated to habitats < 250 m from the roost site. Ponderosa pine and Gambel oak habitats were selected for diurnal activity in greatest proportion to availability throughout all seasons. Seasonal shifts occurred to lower elevations from the Valles Caldera National Preserve (VCNP) to adjacent Santa Fe National Forest and private lands in November and December of all 3 years. Turkeys spent the shortest duration off the VCNP during the winter of 2010-2011 (52 days) as opposed to 107 days during the winter of 2009-2010 and 124 days during the winter of 2008-2009. Turkeys returned to the VCNP between February and April in each of the 3 years. Annual survival Kaplan-Meier estimates varied among years (range=0.33 to 0.80). Lowest seasonal survival of 0.42 (SE=0.14) occurred during winter 2010 (1 Dec 2009-31 March 2010). There were 20 observed mortalities of the 49 monitored turkeys. Predation accounted for 60% (n=12) of mortality during the study with the primary predators identified as bobcats (Lynx rufus) and pumas (Puma concolor) based on hematomas and wounds on the carcass as well as tracks, scats and dorsal guard hairs at the kill sites. Hunter harvest (20%), vehicle collision (5%), disease (5%), and 2 unknown mortalities (10%)- accounted for the remaining mortalities.