Browsing by Subject "Rio Grande wild turkey"
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Item Coyote predation on the Rio Grande wild turkey in the Texas Panhandle and Southwestern Kansas(2005-08) Houchin, Rachael L.; Ballard, Warren B.; Wallace, Mark C.; Gipson, Philip S.; Bonner, JeffFrom January 2000 to August 2004, we collected data on Rio Grande wild turkey (Meleagris gallapavo intermedia) survival, cause-specific mortality, movements, habitat use, roost use, and nesting at 4 study sites (3 in the Texas Panhandle: Matador Wildlife Management Area (MWMA) near Paducah, Texas, Salt Fork of the Red River private land holdings (SF) near Clarendon, Texas, and Gene Howe Wildlife Management Area (GHWMA) near Canadian, Texas, and 1 site on the Cimarron National Grasslands (CNG) near Elkhart, Kansas). During 2000-2002 turkey survival across the 4 sites was about 50% (Ballard et al. 2002). Coyotes were the most frequently cited predators of Rio Grande wild turkeys during the first 3 years of our study, identified in 147 out of 313 (47%) predation events (Ballard et al. 2003). We wanted to further study the impact of coyotes on adult (= 1 year old) and juvenile (6 months to 1 year old) Rio Grande wild turkeys in the Texas Panhandle and Southwestern Kansas, by examining and comparing relative abundances and food habits of coyotes at our four study sites. To estimate relative abundance of carnivore species at our study sites, we used scent stations as our primary method and scat surveys as a secondary method to corroborate scent stations. We examined the food habits of coyotes at our study sites through scat analysis, using scats collected from our scat surveys. Proportions of prey species were expressed using percent of scats (POS) and percent of occurrence(POO). Scent station visitation by coyotes was not different among sites in any season (Fall 2003 ?2 = 7.5067, P = 0.0574; Spring 2003 ?2 = 1.6263, P = 0.6535 Summer 2003 x ?2 = 4.4270, P = 0.2189 and Winter 2004 ?2 = 1.6442, P = 0.6494, Table 2.1). Raccoons (n = 37) were the second-most frequent visitor, and were significantly different among sites during each period (Fall 2003 ?2 = 17.2083, P = 0.0006; Spring 2003 ?2 = 8.8584, P = 0.312 Summer 2003 ?2 = 7.9598, P = 0.0468 and Winter 2004 ?2 = 8.6458, P = 0.0344). Raccoons were detected more frequently at the SF (?2 = 4.5, P = 0.0339) and MWMA (?2 = 4.5, P = 0.0339) than the CNG site during the Spring sampling period. During the Summer period, raccoons were detected more frequently at SF scent stations than at MWMA (?2 = 4.35, P = 0.0370). Raccoons were detected more frequently in the Fall period at the SF than all other sites (CNG 2 = 10.28, P = 0.0013; MWMA ?2 = 7.02, P = 0.0081; GHWMA ?2 = 5.11, P = 0.0237). During the Winter period, raccoons were detected more frequently at SF (?2 = 5.56, P = 0.0184) and GHWMA (?2 = 4.02, P = 0.0450) than MWMA. Diet composition of coyote scats (n = 374) consisted of 27 prey types, primarily small mammal species (n = 11) and vegetation (n = 8), followed by large mammal species (n = 3), medium mammal species (n = 2), avian species (n = 2), reptiles (n = 1), and insects (n = 1). Prey occurrences were primarily small- [n = 194, 40.76 Percent of Occurrence (POO)] and medium-sized (n = 73, 15.33 POO) mammals. The most common prey occurrence across all sites and seasons was Eastern cottontail (Sylvilagus floridanus)(n = 69, 14.50 POO), identified in scats at all sites. White-footed (Peromyscus leucopus), and deer mice (Peromyscus maniculatus), (n = 42, 8.82 POO), and hispid cotton rat (Sigmodon hispidus, n = 28, 5.88 POO) were the most common prey types in the small mammal prey category. We detected avian species (n = 13, 2.73 xi POO) in coyote scats at SF (n = 6), GHWMA (n = 2), and CNG (n = 4) sites. Turkey was <1% of all food items, detected only at SF (n = 2) and CNG (n = 1).Item Coyote predation on the Rio Grande wild turkey in the Texas Panhandle and Southwestern Kansas(Texas Tech University, 2005-08) Houchin, Rachael L.; Ballard, Warren B.; Wallace, Mark C.; Gipson, Philip S.; Bonner, JeffFrom January 2000 to August 2004, we collected data on Rio Grande wild turkey (Meleagris gallapavo intermedia) survival, cause-specific mortality, movements, habitat use, roost use, and nesting at 4 study sites (3 in the Texas Panhandle: Matador Wildlife Management Area (MWMA) near Paducah, Texas, Salt Fork of the Red River private land holdings (SF) near Clarendon, Texas, and Gene Howe Wildlife Management Area (GHWMA) near Canadian, Texas, and 1 site on the Cimarron National Grasslands (CNG) near Elkhart, Kansas). During 2000-2002 turkey survival across the 4 sites was about 50% (Ballard et al. 2002). Coyotes were the most frequently cited predators of Rio Grande wild turkeys during the first 3 years of our study, identified in 147 out of 313 (47%) predation events (Ballard et al. 2003). We wanted to further study the impact of coyotes on adult (= 1 year old) and juvenile (6 months to 1 year old) Rio Grande wild turkeys in the Texas Panhandle and Southwestern Kansas, by examining and comparing relative abundances and food habits of coyotes at our four study sites. To estimate relative abundance of carnivore species at our study sites, we used scent stations as our primary method and scat surveys as a secondary method to corroborate scent stations. We examined the food habits of coyotes at our study sites through scat analysis, using scats collected from our scat surveys. Proportions of prey species were expressed using percent of scats (POS) and percent of occurrence(POO). Scent station visitation by coyotes was not different among sites in any season (Fall 2003 ?2 = 7.5067, P = 0.0574; Spring 2003 ?2 = 1.6263, P = 0.6535 Summer 2003 x?2 = 4.4270, P = 0.2189 and Winter 2004 ?2 = 1.6442, P = 0.6494, Table 2.1). Raccoons (n = 37) were the second-most frequent visitor, and were significantly different among sites during each period (Fall 2003 ?2 = 17.2083, P = 0.0006; Spring 2003 ?2 = 8.8584, P= 0.312 Summer 2003 ?2 = 7.9598, P = 0.0468 and Winter 2004 ?2 = 8.6458, P = 0.0344). Raccoons were detected more frequently at the SF (?2 = 4.5, P = 0.0339) and MWMA (?2 = 4.5, P = 0.0339) than the CNG site during the Spring sampling period. During the Summer period, raccoons were detected more frequently at SF scent stations than at MWMA (?2 = 4.35, P = 0.0370). Raccoons were detected more frequently in the Fall period at the SF than all other sites (CNG ?2 = 10.28, P = 0.0013; MWMA ?2 = 7.02, P = 0.0081; GHWMA ?2 = 5.11, P = 0.0237). During the Winter period, raccoons were detected more frequently at SF (?2 = 5.56, P = 0.0184) and GHWMA (?2 = 4.02, P = 0.0450) than MWMA. Diet composition of coyote scats (n = 374) consisted of 27 prey types, primarily small mammal species (n = 11) and vegetation (n = 8), followed by large mammal species (n = 3), medium mammal species (n = 2), avian species (n = 2), reptiles (n = 1), and insects (n = 1). Prey occurrences were primarily small- [n = 194, 40.76 Percent of Occurrence (POO)] and medium-sized (n = 73, 15.33 POO) mammals. The most common prey occurrence across all sites and seasons was Eastern cottontail (Sylvilagus floridanus)(n = 69, 14.50 POO), identified in scats at all sites. White-footed (Peromyscus leucopus), and deer mice (Peromyscus maniculatus), (n = 42, 8.82 POO), and hispid cotton rat (Sigmodon hispidus, n = 28, 5.88 POO) were the most common prey types in the small mammal prey category. We detected avian species (n = 13, 2.73 xi POO) in coyote scats at SF (n = 6), GHWMA (n = 2), and CNG (n = 4) sites. Turkey was <1% of all food items, detected only at SF (n = 2) and CNG (n = 1).Item Estimating Distribution and Abundance of Rio Grande Wild Turkeys in South Texas(2010-10-12) Caveny, Robert J.Sustainable management of wildlife populations relies on accurate estimates of population size as harvest recommendations are dependent on estimates of sustainable surplus. Techniques for surveying wild turkey populations in Texas are constrained by land access issues, requiring that new methods be developed for population monitoring. I evaluated a combined approach using patch-occupancy modeling at broad spatial scales and intensive double observer roost surveys at local scales to estimate Rio Grande wild turkey (Meleagris gallapavo intermedia) distribution and abundance. I flew replicated aerial surveys during 2007 and 2008 to evaluate distribution of Rio Grande wild turkeys in the south Texas Coastal Sand Plains. I used a double observer approach to estimate local scale abundance. I used a single observer approach to estimate temporal variation in roost use. Detection probabilities from aerial surveys ranged between 0.24 (SE = 0.031) and 0.30 (SE = 0.083). Spatial parameters that influenced distribution of wild turkeys included size of suitable roosting habitat patches and distance to the nearest suitable roosting habitat. I conducted 100 inter-patch double observer roost counts, with counts ranging between 0 to 183 individuals. Average detection probabilities for observers were ~0.90. Roost level occupancy was ~0.84 with detection probabilities between 0.69 (SE = 0.107) and 0.79 (SE = 0.091). Based on my results, aerial surveys combined with local abundance estimation may be one viable alternative to monitor turkey populations over large spatial scales, by reducing overall survey effort without loss of estimated precision.Item Estimating Rio Grande wild turkey densities in Texas(2009-06-02) Locke, Shawn LeeRio Grande wild turkeys (Meleagris gallopavo intermedia) are a highly mobile, wide ranging, and secretive species located throughout the arid regions of Texas. As a result of declines in turkey abundance within the Edwards Plateau and other areas, Texas Parks and Wildlife Department initiated a study to evaluate methods for estimating Rio Grande wild turkey abundance. Unbiased methods for determining wild turkey abundance have long been desired, and although several different methods have been examined few have been successful. The study objectives were to: (1) review current and past methods for estimating turkey abundance, (2) evaluate the use of portable thermal imagers to estimate roosting wild turkeys in three ecoregions, and (3) determine the effectiveness of distance sampling from the air and ground to estimate wild turkey densities in the Edwards Plateau Ecoregion of Texas. Based on the literature review and the decision matrix, I determined two methods for field evaluation (i.e., infrared camera for detecting roosting turkeys and distance sample from the air and ground). I conducted eight ground and aerial forward-looking infrared (FLIR) surveys (4 Edwards Plateau, 3 Rolling Plains, and 1 Gulf Prairies and Marshes) of roost sites during the study. In the three regions evaluated, I was unable to aerially detect roosting turkeys using the portable infrared camera due to altitudinal restrictions required for safe helicopter flight and lack of thermal contrast. A total of 560 km of aerial transects and 10 (800 km) road based transects also were conducted in the Edwards Plateau but neither method yielded a sufficient sample size to generate an unbiased estimate of the turkey abundance. Aerial and ground distance sampling and aerial FLIR surveys were limited by terrain and dense vegetation and a lack of thermal contrast, respectively. Study results suggest aerial FLIR and ground applications to estimate Rio Grande wild turkeys are of limited value in Texas. In my opinion, a method for estimating Rio Grande wild turkey densities on a regional scale does not currently exist. Therefore, the Texas Parks and Wildlife Department should reconsider estimating trends or using indices to monitor turkey numbers on a regional scale.Item Evaluation of road-based surveys of Rio Grande wild turkeys in Texas(2008-12) Erxleben, Devin Ryan; Ballard, Warren B.; Wallace, Mark C.; Butler, Matthew J.Many techniques have been used to index or estimate abundance, density, and trends of Rio Grande wild turkey (Meleagris gallopavo intermedia) populations. Though traditional index-based monitoring techniques can indicate trends in wild turkey populations, they were not designed with the sensitivity necessary to detect anything but drastic changes. Recent research on line transect-based distance sampling from roads has indicated road-based surveys may provide an efficient, effective, and inexpensive technique for monitoring wild turkey populations on an ecoregion scale. Our goal was to evaluate the applicability of road-based distance sampling in the Cross Timbers, Edwards Plateau, Rolling Plains, and South Texas ecoregions of Texas. Our research objectives were to: (1) quantify the association of male and female Rio Grande wild turkeys to roads according to ecoregion, season, and time of day, and examine potential biases associated with using roads as transects for distance sampling; (2) conduct road-based surveys in each ecoregion to determine wild turkey flock encounter rates and the amount of survey effort required to obtain adequate sample sizes for road-based distance sampling; and (3) conduct field simulation surveys using inflatable wild turkey decoys to determine flock detection probabilities and evaluate factors affecting wild turkey flock detectability. We found that Rio Grande wild turkey populations are randomly distributed around roads from 1 December-15 March in most areas. Our results suggested that road-based surveys conducted during that period will produce generally unbiased results. We conducted road-based surveys in 4 ecoregions of Texas from 1 December 2007-15 March 2008. Encounter rates of wild turkey flocks obtained from road-based surveys varied from 0.1 (0.0-0.6; 95% CI) to 2.2 (0.8-6.0) flocks/100 km surveyed. Encounter rates from surveys restricted to riparian communities varied from 0.2 (0.1-0.6; 95% CI) to 2.9 (1.5-6.7) flocks/100 km surveyed. Flock detection probabilities obtained from field simulations ranged from 22.5% (16.3-29.8%; 95% CI) to 25.0% (13.6-39.6%). Flock detection probabilities were lower than expected in each ecoregion, which resulted in low encounter rates. Estimated survey effort required to obtain adequate sample sizes for distance sampling ranged from 2,765 km (2,597-2,956 km; 95% CI) in the Edwards Plateau to 37,500 km (33,333-42,857 km) in South Texas. When road-based surveys were restricted to riparian communities, estimated survey effort ranged from 2,222 km (2,092-2,370 km; 95% CI) in the Edwards Plateau to 22,222 km (19,782-25,349 km) in South Texas. Our modeling efforts suggested that distance to the flock and vegetative cover combined played important roles in wild turkey flock detectability. Frequent rains during the 2007 growing season created dense understory vegetation that made flock detectability difficult in every ecoregion. Our results indicated that too much survey effort was required to make road-based surveys a feasible technique for monitoring wild turkey populations in most ecoregions of Texas. However, when surveys were restricted to areas within 1 km from a river or stream, the technique was feasible for monitoring wild turkey populations in the Edwards Plateau and Rolling Plains ecoregions.Item GIS-based multiple scale study of Rio Grande wild turkey habitat in the Edwards Plateau of Texas(Texas A&M University, 2006-10-30) Perotto Baldiviezo, Humberto LauroRio Grande wild turkey (RGWT) abundance in portions of the Edwards Plateau has declined steadily since the late 1970s as compared to other areas of the Edwards Plateau where populations have exhibited no trend. The reasons for this decline remain unclear. Possible factors include changes in habitat, and increased human population. The overall objective of this study was to identify landscape changes and habitat characteristics that affect RGWT populations using spatial analysis and modeling at multiple spatial scales. Specific objectives for this study included the quantification of flood-induced landscape changes between 1972 and 1995 along the Medina River bottomlands and their impact on RGWT habitat, the quantification of landscape characteristics of stable and declining study sites in the Edwards Plateau, and the development and evaluation of a GIS-based habitat-suitability model for female RGWTs during the breeding season that will allow the assessment of the spatial distribution of adequate habitat in the Edwards Plateau.The analysis of the landscape characteristics along the North Prong Medina River due to flooding in 1978 had a negative impact on RGWT habitat. Changes in the spatial distribution of woody cover in the bottomlands and the removal of woody cover along riparian zones most likely limited habitat use and dispersal of RGWT along the North Prong Medina River. The analysis of landscape characteristics in sites with stable and declining of RGWTs populations showed that disturbance and a high proportion of woody cover were important factors influencing RGWT populations in areas where turkey numbers had declined. Landscape attributes were used as habitat variables to develop a habitat-suitability model for female RGWTs during the breeding season. The model performed well in characterizing high-suitability habitat for adult female RGWT during the breeding season in the study areas. The use of two scales relevant to RGWT provided important information about the high-suitability areas for female RGWT in stable and declining sites in the Edwards Plateau.Item Influences of vegetation characteristics and invertebrate abundance of Rio Grande wild turkey populations, Edwards Plateau, Texas(Texas A&M University, 2005-02-17) Randel, Charles JackSince 1970, Rio Grande wild turkey (Meleagris gallapavo intermedia) numbers in the southern region of the Edwards Plateau of Texas have been declining. Nest-site characteristics and invertebrate abundance were hypothesized as limiting wild turkey numbers in declining regions. Wild turkeys were trapped and fitted with mortality-sensitive radio transmitters on 4 study areas; 2 within a region of stable (northern Edwards Plateau) populations, and 2 within a region of declining populations. Monitoring occurred from February 2001 to August 2003. Nest-site locations were determined via homing during the breeding season. Following nesting attempts/completions, nest fate, vegetation height, visual obstruction, litter depth, percent cover, and cover scores of forbs, grass, litter, and bare ground at each nest site and surrounding area were sampled. This was done to determine if wild turkey hens selected nest sites with vegetative characteristics differing from surrounding habitat. Brood survival was calculated as >1 poult surviving to 2-weeks. Broods were followed for 6-weeks post-hatch or to brood failure. Invertebrates were collected, via sweep-net and D-vac, at each visually confirmed brood location and a paired random site to determine if wild turkey hens selected brood habitat based on invertebrate abundance. Analyses were performed to determine if invertebrate abundance differed between study regions. Turkey hens selected nest sites with greater visual obstruction and more litter depth on both regions of stable and declining turkey abundance. No vegetative differences were detected between stable and declining region nest sites. Frequency of Orthoptera was 3?5 times greater at nest sites on stable regions than declining regions in all 3 years. Orthoptera is a noted food source for young galliformes and comprised the majority of dry mass in invertebrate samples, nest sites and brood locations, on both the stable and declining regions. No differences in total invertebrate dry mass were detected between regional brood locations. Nest-site vegetative characteristics did not alter nest success between regions. The 2 overall objectives of this study were to determine if nest-site vegetation characteristics and invertebrate abundance affected wild turkey numbers in the Edwards Plateau. Regional differences in vegetative characteristics were not detected, thus not likely to be causing differences in turkey numbers between regions. Nest-site invertebrates were found to be 3?5 times greater at stable region nest sites, possibly giving wild turkey poults from stable regions greater initial chances of survival.Item Ranges, movements, and spatial distribution of radio-tagged Rio Grande wild turkeys in the Edwards Plateau of Texas(Texas A&M University, 2006-08-16) Schaap, Jody NealTo determine possible causes of declining Rio Grande wild turkey (RGWT; Meleagris gallopavo intermedia) abundance in the southern Edwards Plateau, research was conducted on 4 sites, 2 with stable (S [SA and SB]; Kerr and Real counties) and 2 with declining (D [DA and DB]; Bandera County) RGWT populations. RGWTs were trapped, radio-tagged, and tracked. Ranges were constructed with 95% kernels. Data on brood survival and invertebrate and predator abundances were combined with range characteristics to assess habitat at a landscape scale. Annual range sizes did not differ in year 1, but were larger in S than in D in year 2. Range sizes in S increased from year 1 to year 2 while there was no change in range sizes in D. Range overlap was higher in D than S in both years. Movement distances remained consistent in S for both years, but were larger in D during year 1. During year 1 and year 2, RGWT females exhibited larger reproductive ranges and less range overlap in S. Invertebrate abundance for 4 insect orders was 2.5??15.9 times greater in S than in D while coyote abundance was 2??3 times greater in D than in S. Results were similar in year 3, with the exception of SB, where reproductive ranges and spatial arrangement were smaller than all other sites. My results refute the conventional assumption that larger ranges are indicative of poorer habitat quality. Range overlap suggests that useable space may have been limiting in D in the less productive year 2. In D, multiple broods used the same reproductive range, presumably depleting resources faster than in S. Greater predator abundance in D increased the risk of brood predation. The smaller reproductive spatial arrangement of SB females in year 3 correlates there being >3 times the percentage of females missing in other sites. If SB females moved further in year 3 than the detection distance of the radio telemetry equipment, the results would fit the pattern of greater dispersion distance in SA. RGWT females may attempt to separate themselves from other breeding females, possibly to avoid nest or brood predation and/or potential competition for brood resources.Item Reproductive ecology of Rio Grande wild turkey in the Edwards Plateau of Texas(2009-05-15) Melton, Kyle BradyThe 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.Item Winter roosting ecology of Rio Grande wild turkeys in the Rolling Plains of Texas(2007-05) Swearingin, Ryan Matthew; Wallace, Mark C.; Ballard, Warren B.; Ruthven, Donald C.A crucial time for Rio Grande wild turkeys (Meleagris gallopavo intermedia) is during the winter when flocks >200 birds congregate at traditional winter roosts. As wild turkey home ranges are smallest during this time of year, there is a need for appropriate forage and security habitat in close proximity to suitable roosting habitat. In addition, it is believed that eastern cottonwood (Populus deltoides), the favored roost tree species in the Rolling Plains, may be declining due to altered river flow regimes, the invasion of exotic species such as Russian olive (Elaeanus angustifolia) and saltcedar (Tamarix chinensis), and overgrazing. Consequently, a greater understanding of the critical vegetative characteristics of winter roost sites is needed. We conducted fieldwork on 3 study sites located in the Rolling Plains of Texas during September through flock breakup in April 2004–2006. We gathered roost locations via radiotelemetry to identify movement patterns and to detect active roosts during winter. We measured roosting habitat at 32 roost sites and 32 randomly selected non-roost sites. We measured tree height, tree diameter, canopy cover, tree decay, area of the stand in which the roost occurred (stand area), percent litter cover, and percent shrub cover. We linked winter roost use (presence-absence) with habitat variables representing forest and vegetation structure at roost sites by creating explicit habitat models. We developed 44 a priori logistic regression models. We used second-order Akaike’s information criterion (AICc) for model selection. We found tree height, tree diameter, stand area, and percent litter were all important predictors of roost site occupancy. Based on these findings an appropriate management strategy should include the conservation of large, open-understory, riparian stands of trees. Those stands should contain the tallest, largest diameter trees available. We also suggest that young stands of preferred roost tree species be protected to provide future potential roost sites when current roosts become unsuitable to wild turkeys. Winter flock congregations of Rio Grande wild turkeys are larger than other turkey subspecies. Roosting flocks > 200 birds are not uncommon. However, thorough evaluation of when flocks congregate on winter areas and the potential climatic factors that drive congregation are lacking. We used opportunistic flock counts (n = 3,047) and roost counts (n = 101) to identify timing of winter flock congregation, peak concentrations, and breakup of winter roosts. We also examined possible relationships between roost/flock counts and climatic variables. We found that winter congregation occurred from 15 November through 28 February with peak concentrations occurring from 16 January through 1 March, and flock breakup occurred from 1 March through 15 April. We suggest that if using roost counts for abundance estimation that surveys be conducted from 16 January though 1 March.