Turkey Productivity in Two Vegetative Communities in South Texas

Abstract

Differences in productivity of the Rio Grande turkey (Meleagris gallopavo intermedis) between mesquite (Prosopsis juliflora) and live oak (Quercus virginiana) vegetative communities on the King Ranch in South Texas were investigated from June 6, 1968, to January 3, 1969. The average brood size in August for the mesquite area, as determined from 1,720 poult observations, was 6.9, while 721 poult observations on the live oak area revealed an average brood size of 4.6 The overall poult: hen ratios at this same ffme were 4.7 and 2.6 while the hens seen without poults xrere 31 and 40 percent respectively. The August productivity, or percent of increase in the population due to reproduction, was 336 percent for the mesquite area and 159 for the live oak. The November, or pre-hunting season productivities were 315 and 129 percent. Poult mortality for the 13-week period, between 2 and 15 weeks of age, was calculated to be 22.9 percent for the mesquite area and 12.1 for the live oak. A helicopter census yielded a calculated density of 56 turkeys per 1,000 acres on the mesquite area and 51 on the live oak. Road counts revealed overestimations of these densities ranging from 95-193 percent. Turkey productivity on the King Ranch in South Texas has fluctuated tremendously from year to year. In years of normal precepitation, production has been good, whereas in dry years there has been almost no production of young turkeys ( W. H. Kiel, Jr., personal communication). There are several possible ecological explanations for this situation, all of which may be related to the limited vegetation during dry years. An assessment was made of the turkey productivity in two vegetative communities, mesquite and live oak. This assessment, in two different environments, explored some of the ecological causes of poor turkey productivity. Field work was carried out from June 8, 1968, to January 3, 1969. Turkey densities on the King Ranch have been reported as being considerably greater in live oak than mesquite (Lehmann 1957 ) . In order that the live oak areas maintain higher turkey densities, there must be, through time, either higher productivity, survival, immigration, or some combination of these factors. 1 Research was supported by King Ranch, Inc., University of Wisconsin, and the Ceasar Kleberg Wildlife Foundation. 166 I gratefully acknowledge W. H. Kiel) Jr.7 biologistv King Range, Inc., and R. A. McCabe of the University of Wisconsin for advice, assistance, and editorial help throughout this project. O. J. Rongstad of the University of Wisconsin, provided suggestions in preparing the manuscript.