Reproductive Success and Nesting Habitat of Merriam's Wild Turkeys in Oregon

Abstract

Reproductive success and nesting habitat were described for 25 Merriam's wild turkey (Meleagris gallopavo merriami) hens in northcentral Oregon during 1981-82. A higher proportion of adults than yearlings attempted to nest (75 vs. 25%) and were more successful (90 vs. 25%). Nests were located in five of 14 available cover types. Only Thinned, Mixed Conifer was used significantly more than it occurred. Thinned, Mixed Conifer stands contained 52% of the nests, of which 82% were successful. Two measurements of vegetative screening (shrub density and visual obstruction at 0.5 m) were significantly greater at sites used for nesting than at random sites. We recommend creating nesting habitat by thinning pole-size Douglas-fir (Pseudotsuga menziesii) stands and leaving slash in stands. Additionally, adult rather than yearling hens should be released in transplant operations. J. WILDL. MANAGE. 51(4):783-787 Quantitative measures of nesting habitats and nest success of Merriam's wild turkeys can provide information useful for managing nesting habitat. Similarly, knowledge of nest-site characteristics and nesting habitat selection can be used by managers for evaluating potential release sites. Limited information is available on productivity and nesting habitat for populations of this subspecies. Low nesting rates and reproductive success of yearling hens may have limited reproduction of Merriam's turkeys in New Mexico (Lockwood and Sutcliffe 1985). Nesting habitat has been described as lightly cut-over areas in Mixed Conifer stands in New Mexico (Jones 1981), ponderosa pine (Pinus ponderosa) in Arizona (Phillips 1982) and South Dakota (Petersen and Richardson 1975), and white oak (Quercus garryana )-Douglas-fir in Washington (Mackey 1982). None of these studies, however, addressed nesting success in relation to habitat selection. Accordingly, the objectives of this study were to determine reproductive success, nestsite selection, and reproductive success in relation to available habitat, and to describe nestsite characteristics of Merriam's wild turkeys in Oregon. Oreg. Dep. Fish and Wildl. and Mount Hood Natl. For. provided funding for the project. During all phases of the project, R. R. Denney and D. P. Longrie were most helpful. We thank R. G. Anthony, W. C. Krueger, and T. F. Haensly for their manuscript reviews and C. A. Heath for help with collection of field data. This is Tech. Pap. 7827 of the Oreg. Agric. Exp. Stn. METHODS This study was conducted in southern Wasco County, Oregon, in 1981 and 1982. Merriam's wild turkeys were introduced into this area in 1961. The 135,141-ha study area encompassed portions of Mount Hood National Forest, the Oregon Department of Fish and Wildlife White River Game Management Area, the Confederated Tribes of Warm Springs Reservation, and adjacent private holdings. Study area boundaries were defined by the movements of radiomarked turkeys. The area was located primarily within the Douglas-fir and ponderosa pine forest zones described by Franklin and Dyrness (1973). Specific cover types were defined according to the dominant vegetation and land use practices and were delineated from LANDSAT satellite imagery. Oak Woodland (24.6%) was the most abundant of the 14 cover types present; other major cover types included Ponderosa Pine (17.8%), Mature Mixed Conifer (14.2%), and Ponderosa Pine-Douglas-fir-Oak (12.5%). Elevation ranged from 610 to 1,067 m. Turkeys were trapped from 1 January to 5 April each year with a modified walk-in trap (Ligon 1946) consisting of 4 welded wire panels (1 x 3 m) and a net wire (10 x 10 cm) top. Age and sex of birds were determined by the presence or absence of barring on the 9th and 10th primaries and breast feather coloration (Larson and Taber 1980). Transmitters, weighing 90 g and with an operational life of 12-15 months, were attached with a backpack harness of rubber tubing covered by braided nylon.