Since 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.

To 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.

Since 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.

To 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.

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.