29 research outputs found

    Incubation recess behaviors influence nest survival of Wild Turkeys

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    In ground nesting upland birds, reproductive activities contribute to elevated predation risk, so females presumably use multiple strategies to ensure nest success. Identification of drivers reducing predation risk has primarily focused on evaluating vegetative conditions at nest sites, but behavioral decisions manifested through movements during incubation may be additional drivers of nest survival. However, our understanding of how movements during incubation impact nest survival is limited for most ground nesting birds. Using GPS data collected from female Eastern Wild Turkeys (n = 206), we evaluated nest survival as it relates to movement behaviors during incubation, including recess frequency, distance traveled during recesses, and habitat selection during recess movements. We identified 9,361 movements off nests and 6,529 recess events based on approximately 62,065 hr of incubation data, and estimated mean nest attentiveness of 84.0%. The numbers of recesses taken daily were variable across females (range: 1-7). Nest survival modeling indicated that increased cumulative distance moved during recesses each day was the primary driver of positive daily nest survival. Our results suggest behavioral decisions are influencing trade-offs between nest survival and adult female survival during incubation to reduce predation risk, specifically through adjustments to distances traveled during recesses

    Space Use, Daily Movements, and Roosting Behavior of Male Wild Turkeys During Spring in Louisiana and Texas

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    Because wild turkeys (Meleagris gallopavo) are an important game species and turkey hunter numbers are increasing, the need for better information on how turkeys use their environment is critical. With the recent advent of GPS technology suitable for use on wild turkeys, we are now able to collect data on a scale not previously possible. We used backpack style GPS units to detail home range and core area sizes, daily movement distances, and roosting characteristics of male Eastern (M. g. silvestris) and Rio Grande (M. g. intermedia) wild turkeys in Louisiana and Texas. Mean home range size was larger in Louisiana (383 ha) than in Texas (270 ha), and mean distance between consecutive roost sites was farther in Louisiana (803 m) than in Texas (211 m). However, average daily distance traveled was shorter in Louisiana (3725 m) than in Texas (4608 m). The mean distance between consecutive roost sites was 803m in Louisiana and 211m in Texas. Our findings suggest that space use and daily movements of male wild turkeys vary little from Eastern to Rio Grande, but that roosting habits and movements associated with roosting differ strongly. Managers should recognize that availability of roost sites may greatly influence daily movements and behavior of Rio Grande wild turkeys but may have limited impacts on Eastern wild turkeys

    Patterns of survival and roost switching in an African insectivorous bat

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    Variation in survival over time and amongst age and sex classes drives population dynamics for a large majority of long-lived species and is critical to understanding species demography. For highly mobile species that actively move among potential breeding locations, coupling survival information with estimates of locational fidelity provides the basis for our understanding of species population dynamics. We studied the effect of time, age and sex class, and climatic variables on survival and roost transition probabilities on a population of Egyptian slit-faced bats in Swaziland from 1450 marked individuals from 16 roosts over a 10 year period. We then used variance components analysis to estimate average annual survival and associated temporal process variance. Annual apparent survival varied with sex and age, being highest in adult males and lowest in juvenile females. We did not find evidence of survival being influenced by climatological factors as commonly observed in temperate bats. Roost switching occurred frequently, with more transitions to roosts harboring larger number of bats. Furthermore, the probability of transitioning to another roost was related to its distance from the original roost. The dispersal patterns revealed in this study were consistent with the fission-fusion dynamics common for colonial bats.http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1469-79982016-05-31hb2015Zoology and EntomologyMammal Research Institut

    Behavioral strategies during incubation influence nest and female survival of Wild Turkeys

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    Females must balance physiological and behavioral demands of producing offspring with associated expenditures, such as resource acquisition and predator avoidance. Nest success is an important parameter underlying avian population dynamics. Galliforms are particularly susceptible to low nest success due to exposure of ground nests to multiple predator guilds, lengthy incubation periods, and substantive reliance on crypsis for survival. Hence, it is plausible that nesting individuals prioritize productivity and survival differently, resulting in a gradient of reproductive strategies. Fine-scale movement patterns during incubation are not well documented in ground-nesting birds, and the influence of reproductive movements on survival is largely unknown. Using GPS data collected from female wild turkeys (n = 278) across the southeastern United States, we evaluated the influence of incubation recess behaviors on trade-offs between nest and female survival. We quantified daily recess behaviors including recess duration, recess frequency, total distance traveled, and incubation range size for each nest attempt as well as covariates for nest concealment, nest attempt, and nest age. Of 374 nests, 91 (24%) hatched and 39 (14%) females were depredated during incubation. Average nest survival during the incubation period was 0.19, whereas average female survival was 0.78. On average, females took 1.6 daily unique recesses (SD = 1.2), spent 2.1 hr off the nest each day (SD = 1.8), and traveled 357.6 m during recesses (SD = 396.6). Average nest concealment was 92.5 cm (SD = 47). We found that females who took longer recess bouts had higher individual survival, but had increased nest loss. Females who recessed more frequently had lower individual survival. Our findings suggest behavioral decisions made during incubation represent life-history trade-offs between predation risk and reproductive success on an unpredictable landscape

    Special Section The Prevailing Paradigm as a Hindrance to Conservation

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    ABSTRACT We review the history of population and ecological knowledge of the golden-cheeked warbler (Setophaga chrysoparia). We highlight how incomplete information on distribution and abundance has led to substantial misunderstanding on species status and associated conservation goals. We discuss how once a paradigm is established, subsequent studies unconsciously fortify accepted understanding regardless of the paradigm's accuracy. For the golden-cheeked warbler, understanding of the species at the time of listing in 1990 was based on either incorrect or untested assumptions of species distribution within available habitats. Adhering to untested assumptions led to development of priorities for research and management that were well-intentioned but largely misguided. Ample information on the distribution of the warbler's habitats existed, however, which should have encouraged questions into the basis of population conditions when developing management prescriptions. Current knowledge clearly indicates that a new paradigm for the warbler is needed, that being one of a widely distributed species that is preadapted to occur within a variety of environmental conditions. ß 2012 The Wildlife Society

    Dynamic edge effects in small mammal communities across a conservation-agricultural interface in Swaziland

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    Across the planet, high-intensity farming has transformed native vegetation into monocultures, decreasing biodiversity on a landscape scale. Yet landscape-scale changes to biodiversity and community structure often emerge from processes operating at local scales. One common process that can explain changes in biodiversity and community structure is the creation of abrupt habitat edges, which, in turn, generate edge effects. Such effects, while incredibly common, can be highly variable across space and time; however, we currently lack a general analytical framework that can adequately capture such spatio-temporal variability. We extend previous approaches for estimating edge effects to a non-linear mixed modeling framework that captures such spatio-temporal heterogeneity and apply it to understand how agricultural land-uses alter wildlife communities. We trapped small mammals along a conservation-agriculture land-use interface extending 375 m into sugarcane plantations and conservation land-uses at three sites during dry and wet seasons in Swaziland, Africa. Sugarcane plantations had significant reductions in species richness and heterogeneity, and showed an increase in community similarity, suggesting a more homogenized small mammal community. Furthermore, our modeling framework identified strong variation in edge effects on communities across sites and seasons. Using small mammals as an indicator, intensive agricultural practices appear to create high-density communities of generalist species while isolating interior species in less than 225 m. These results illustrate how agricultural land-use can reduce diversity across the landscape and that effects can be masked or magnified, depending on local conditions. Taken together, our results emphasize the need to create or retain natural habitat features in agricultural mosaics.Texas A&M Agrilife Researchhttp://www.plosone.orgam2013Zoology and EntomologyMammal Research Institut

    Breeding and non-breeding survival of lesser prairie-chickens Tympanuchus pallidicinctus in Texas, USA

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    Lesser prairie-chickens Tympanuchus pallidicinctus have declined throughout their range because of loss or fragmentation of habitat from conversion of native prairie to agricultural cropland, exacerbated by overgrazing and drought. We used data from radio-marked lesser prairie-chickens to determine whether differences in survival existed between populations occurring in two areas dominated by different vegetation types (sand sagebrush Artemisia filifolia vs shinnery oak Quercus havardii) in the Texas Panhandle from 2001 through 2005. We used a model-selection approach to evaluate potential generalities in lesser prairie-chicken survival. Our results indicated that survival of lesser prairie-chickens differed between breeding and non-breeding periods, and between study populations. We estimated annual survival of lesser prairie-chickens at 0.52 (95% CI: 0.32-0.71) in the sand sagebrush and 0.31 (95% CI: 0.12-0.58) in the shinnery oak vegetation type. Our results suggest that demographic differences in lesser prairiechicken within sand sagebrush and shinnery oak vegetation types throughout the Texas Panhandle should be evaluated, especially during the breeding season. Based on our results, higher mortality of birds during the breeding season illustrates the need to manage for vegetation components such as sand sagebrush and residual bunchgrasses as opposed to shinnery oak such that potential breeding season mortality may be lessened

    Foreign Aid as a Signal to Investors: Predicting FDI in Post-conflict Countries

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    Does development aid attract foreign direct investment (FDI) in post-conflict countries? This article contributes to the growing literature on effects of aid and on determinants of FDI by explaining how development aid in low-information environments is a signal that can attract investment. Before investing abroad, firms seek data on potential host countries. In post-conflict countries, reliable information is poor, in part because governments face unusual incentives to misrepresent information. In these conditions, firms look to signals. One is development aid, because donors tend to give more to countries they trust to properly handle the funds. Our results show that aid seems to draw FDI—however, this is conditional on whether the aid can be considered geostrategically motivated. We also show that this effect decreases as time elapses after the conflict. This suggests that aid’s signaling effect is specific to low-information environments, and helps rule out alternative causal mechanisms linking aid and FDI

    Space Use, Daily Movements, and Roosting Behavior of Male Wild Turkeys During Spring in Louisiana and Texas

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    Because wild turkeys (Meleagris gallopavo) are an important game species and turkey hunter numbers are increasing, the need for better information on how turkeys use their environment is critical. With the recent advent of GPS technology suitable for use on wild turkeys, we are now able to collect data on a scale not previously possible. We used backpack style GPS units to detail home range and core area sizes, daily movement distances, and roosting characteristics of male Eastern (M. g. silvestris) and Rio Grande (M. g. intermedia) wild turkeys in Louisiana and Texas. Mean home range size was larger in Louisiana (383 ha) than in Texas (270 ha), and mean distance between consecutive roost sites was farther in Louisiana (803 m) than in Texas (211 m). However, average daily distance traveled was shorter in Louisiana (3725 m) than in Texas (4608 m). The mean distance between consecutive roost sites was 803m in Louisiana and 211m in Texas. Our findings suggest that space use and daily movements of male wild turkeys vary little from Eastern to Rio Grande, but that roosting habits and movements associated with roosting differ strongly. Managers should recognize that availability of roost sites may greatly influence daily movements and behavior of Rio Grande wild turkeys but may have limited impacts on Eastern wild turkeys

    Nest Site Selection and Nest Survival of Eastern Wild Turkeys in a Pyric Landscape

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    Pine (Pinus spp.)-dominated forests are commonly managed with prescribed fire in the southeastern United States to reduce fuel loads, maintain diverse plant communities, and increase habitat quality for wildlife. Prescribed fire alters understory vegetation, which is a key component of nesting habitat for ground-nesting birds. We assessed the influences of vegetation, prescribed fire, and landscape features (e.g., roads, edge) on nest site selection and nest survival of eastern wild turkeys (Meleagris gallopavo silvestris) in a pine-dominated ecosystem in west-central Louisiana. We radio-marked 55 female wild turkeys and evaluated vegetation and landscape characteristics associated with 69 nests during the 2014 and 2015 reproductive periods. We used conditional logistic regressions with matched-pairs case-control sampling and information-theoretic approaches to determine if vegetation characteristics within 15m of a nest site, distances to surrounding vegetation communities and edges, and prescribed fire history of patches where a nest was located influenced nest site selection. We calculated hazard ratios for covariates in our top-performing models to determine if any of these characteristics affected nest site survival. Turkeys in our study had a longer reproductive season and higher nesting and renesting rates relative to other populations in the southeastern United States. At the local scale, turkeys nested in areas with higher percent ground cover vegetation. At the landscape scale, turkeys nested closer to roads and farther from edges of 2 plant communities. Turkeys selected to nest in forest stands burned 2 years prior. Nest survival was not affected by percent ground cover, distance to roads, or distance to edge but was negatively associated with time-since fire; turkey nests in stands burned ≥3 years prior had lower survival than nests in stands burned the current year. We suggest that burning on a 3-year fire return interval is compatible with management for wild turkeys in southeastern pine-dominated forests. Includes supporting information
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