Survival of Wild Turkey Hens in North Missouri

Abstract

Survival and cause-specific mortality of wild turkey (Meleagris gallopavo silvestris) hens were investigated in north Missouri during 1984-85. Survival estimates and distributions were calculated using the Kaplan-Meier product-limit method from a sample of 60 radio-marked hens. The annual survival rate was 0.435 ? 0.073. Predation and poaching were the major causes of mortality, accounting for 54.9 and 38.7% of the losses, respectively. Legal fall harvest was responsible for only 3.2% of the deaths and was considered a minor cause of mortality. Seasonal losses were highest during spring. Forty-two percent of the illegal hen kills occurred during the spring gobbler season. Survival probabilities with poaching or predation as the only source of mortality followed similar patterns. J. WILDL. MANAGE. 51(1):188-193 Wild turkey populations in the mixed timber-agricultural regions of the Midwest have been reported to exceed 30 birds/km2 of timber (Hanson 1984, Lewis and Kurzejeski 1984). Effective management of these populations requires quantitative data on hen turkey survival. Radio-telemetry data have been used to examine survival in reintroduced turkey populations (Swank et al. 1985), expanding turkey populations (Porter 1978), and indigenous turkey populations in the traditional southern range (Everett et al. 1980, Holbrook and Vaughan 1985). Data on survival rates and causes of turkey mortality are scarce, and estimates of hen wild turkey survival are lacking for established populations in the Midwest. Estimates of hen turkey survival are important in the formulation of fall harvest recommendations and as an indication of reproductive potential. Furthermore, determining seasonal and cause-specific survival provides inference as to the relative importance of natural, illegal, and where appropriate, legal harvest mortality. The objectives of this study were to determine annual and seasonal survival and causes of mortality for hen wild turkeys in north Missouri during March 1984-March 1985. We thank V. L. Kimmel for coordinating and conducting the fieldwork, and E. A. Keyser, J. S. Fleming, D. J. Neuswanger, and B. J. Otten for assistance in trapping turkeys. C. J. Scriven, M. E. Wade, C. Turner, E. R. Jayne, and numerous others provided access to their private lands that was essential in conducting this study. S. R. Winterstein, C. Bunck, and S. L. Sheriff provided assistance with data analyses. Partial funding for this study was provided by the Mo. State Chapter and various local chapters of the Natl. Wild Turkey Fed. This study also was supported, in part, by funds supplied by the Fed. Aid to Wildl. Restor. Act, under PittmanRobertson Proj. W-13-R-38. S. S. Sapp typed drafts of the manuscript. The manuscript was reviewed by K. C. Sadler, O. A. Torgerson, R. W. Cannon, S. R. Winterstein, and L. M. Smith. STUDY AREA AND METHODS Hen wild turkeys were captured, radio instrumented, and released in a 52-km2 area in Adair County, Missouri, about 8 km west of Kirksville. The topography is rolling with elevations ranging from 226 to 297 m. Forested land comprises 59.6% of the area. Agricultural lands comprise the remainder, with 16.2% of the area in row crops and 24.2% in pasture. The timber component is 2nd growth oak (Quercus spp.) and hickory (Carya spp.) predominated by pole-sized stands. The floodplain of the Chariton River, which bisects the study area, contains a majority of the cropland. The upland portions of the area are a mosaic of timber interspersed with pastures and hayfields. Trapping was conducted using cannon nets during 2 periods (1 Aug-15 Oct 1983 and 1 Jan-13 Mar 1984). Hens were aged, radio instrumented, and released at the capture site. Transmitters were attached using a backpack harness. The 140-g radio package included a