Reproductive Ecology of Rio Grande Wild Turkey in the Edwards Plateau of Texas


Book Description

The abundance of Rio Grande wild turkeys (Meleagris gallopavo intermedia) in the southeastern Edwards Plateau of Texas has declined since the late 1970s. Because knowledge of reproductive rates is important to understanding the dynamics of a population, radio-tagged hens were monitored during the 2005-2007 reproductive seasons to evaluate and compare reproductive parameters from areas with both declining and stable population trends. During January-March of 2005-2007, turkey hens were captured and radiotagged on 4 study areas; 2 within a region of stable turkey populations, and 2 within a region of declining populations. Monitoring occurred from January-July each season to determine nest- site locations. Nesting attempts, nest fate, clutch size, initiation date, and nest age were recorded. Nests were monitored>̲3 times weekly in order to estimate production parameters and daily nest survival. Poults were captured by hand and fitted with a 1.2 glue-on transmitter and monitored daily to estimate daily survival. Estimates show production was greater in stable regions than declining regions of the Edwards Plateau. Eighty-four percent of hens attempted to nest in the stable region and 67% attempted in the declining region. Eighteen of 102 nests were successful (>̲1 egg hatched), in the stable region and 7 of 60 nests were successful in the declining region. Nest-survival analysis showed an influence of temporal variation within years, yet no differences in nest survival were detected between stable and declining regions. Poult survival also showed no difference between regions. The 2 overall objectives of this study were to determine if nesting parameters and nest survival were limiting factors in Rio Grande wild turkey abundance in the Edwards Plateau. Regional differences in production suggest the cause of the decline in the southeastern portion of the Edwards Plateau could be associated with lower reproductive output and consequently, success. Regional differences in nest survival were not detected, thus not likely to cause differences in turkey abundance between regions.







Wild Turkeys in Texas


Book Description

The wild turkey is an iconic game bird with a long history of association with humans. Texas boasts the largest wild turkey population in the country. It is the only state where one can find native populations of three of the five subspecies of wild turkeys—the Eastern wild turkey (Meleagris gallopavo silvestris), the Rio Grande wild turkey (M. g. intermedia), and the Merriam’s wild turkey (M. g. merriami). Bringing together experts on game birds and land management in the state, this is the first book in Texas to synthesize the most current information about ecology and management focused exclusively on these three subspecies. Wild Turkeys in Texas addresses important aspects of wild turkey ecology and management in Texas, but its principles are applicable anywhere Eastern, Rio Grande, or Merriam’s turkeys exist. This book marks the continuation of one of the biggest success stories in the research, restoration, and management of the wild turkey in North America.







Survival, Home Range Size, Habitat Selection, and Reproductive Ecology of Eastern Wild Turkeys in East Texas


Book Description

Historically, eastern wild turkeys (Meleagris gallopavo silvestris) occupied an estimated 12 million ha in east Texas, but overharvesting of both turkeys and timber led to their near extirpation from the region by 1900. Despite >70 years of restoration efforts, including translocation of >7,000 wild-captured eastern turkeys from >10 states since the late 1970s, estimated east Texas turkey densities remain low. Moreover, regional research has reported poor reproductive performance of translocated turkeys, heightening concerns regarding long-term stability, expansion, and permanence of turkey populations in east Texas. Although previous restoration attempts have involved traditional block-stocking and supplemental-stocking approaches (i.e., release of 15--20 turkeys per site), the use of larger release sizes (i.e., 'super-stocking'; 70 turkeys per site), may be more successful. During 2007 and 2008, 37 resident female turkeys were captured at two sites within the region, fitted with transmitters, and released at respective capture sites. An additional 347 eastern wild turkeys were captured in South Carolina and Tennessee and translocated to four sites in east Texas to evaluate the effectiveness of super-stocking in regional turkey restoration. Prior to release, 178 (115 females/63 males) turkeys were fitted with radio-transmitters and divided among sites; release sizes varied from 83--94, with approximately 45 transmittered turkeys per site. Specifically, the objectives of this research were to quantify survival, home range size, habitat selection, and reproductive ecology of both resident and translocated wild turkeys. Annual survival of resident female turkeys ranged between 0.38--0.68. Annual survival of translocated turkeys during the release year ranged from 0.55--0.71 (x̄ = 0.63) and from 0.73--1.00 (x¯ = 0.85) among sites for female and male turkeys, respectively. Female survival tended to increase in the second year following release (range: 0.63--0.82; x¯ = 0.73), while male survival tended to decrease (range: 0.47--0.66; x¯ = 0.54). Most mortality of resident and translocated females occurred during spring; male mortality was nearly evenly distributed throughout the annual cycle. Resident turkey home ranges averaged 1,146 ha in spring and mean summer home range size ranged from 628--1,118 ha between sites. Spring home ranges of translocated turkeys (x¯ = 901 ha) were larger than summer (x¯ = 443 ha), and female (x¯ = 846 ha) and male (x¯ = 498 ha) home range sizes were similar. Burned and/or thinned pine forests, mixed forests, and herbaceous openings were preferred spring and summer habitats, whereas pre-thin pine forests and forested wetlands were used less frequently by both resident and translocated turkeys. Twenty-five and 74 nests were initiated by resident and translocated hens, respectively. Nesting and renesting rates of resident hens averaged 0.66 and 0.29, respectively. Nesting rates of translocated turkeys varied substantially (range: 0.15--0.77) among sites during the release year, but tended to increase the year following release (range: 0.69--0.92). Renesting rates of translocated hens were considerably lower, averaging 0.21 across sites and years. Most nests of resident and translocated hens were located in thinned and/or burned pine forests, with nests generally having greater ground/screening cover and greater living woody vegetation (%)










Nesting Ecology of Rio Grande Wild Turkeys in the Edwards Plateau of Texas


Book Description

Rio Grande wild turkey (Meleagris gallopavo intermedia) numbers in the southeastern region of the Edwards Plateau (EP) have shown a significant decline since the 1970s; however, the remainder of the EP had stable populations during this period. Since 2001, research has been conducted in the southeastern EP evaluating factors which could be responsible for the decline of Rio Grande turkeys in this region of Texas. I used digital cameras to evaluate the effect of nest predation on the reproductive success of Rio Grande wild turkeys in the region. Nest predation was the leading cause of nest loss in my study and I documented frequent predation events involving 9́Æ1 predator species. While studying nest predation, I examined the effects of my methods, and those commonly used by others, on nest success. Nests with cameras failed at the same frequency as those without cameras but at a faster rate. Predation rates observed for artificial nests underestimated predation rates of real nests. Additionally, I photographed known turkey nest predators at 27% of random points with no eggs, suggesting that nest predation could be a random process depending on the nest predator0́9s unique search image. I also examined the spatial structure of the habitat surrounding nest locations of turkeys on my study sites to evaluate the effect of disturbance on nest-site selection. Out of 59 nests located on the Kerr Wildlife Management Area from 2005 through 2007, only 5 were in areas that had not been burned in the 9 years prior. Turkeys in my study consistently chose areas characteristic of the fire maintained, oak0́3juniper savanna historically found in the region.