Clinton T. Moore

Survival rates of bobwhite quail based on band recovery analyses

We present the results of a long-term (1970-85) band recovery study of northern bobwhite quail (Colinus virginianus) at Tall Timbers Research Station, Leon County, Florida. The mean annual survival rate of male quail (18.7 ? 1.2 [SE] %) was significantly (P = 0.01) greater than that of females (14.3 ? 1.2%). The difference between survival of young (6-9 months old) and adults (>1 yr old) was 3 ? 2.2% and not significant. Survival rates varied significantly among years. The mean harvest was 23.3 ? 0.53%/year. Young male quail were harvested at a significantly higher rate than adult males (2% difference). There was no significant difference between harvest rates of young and adult females. Juvenile male and female harvest rates were not significantly different. However, adult females were harvested at a significantly higher rate than adult males (5% difference). Harvest varied among years. The mean annual kill (harvest rate + crippling loss) was approximately 30% for both sexes. Male and female natural mortality were approximately 52 and 56%, respectively. There was evidence of additivity of hunting and natural mortality for this population harvested in late winter. Our long-term study provides information on the survival processes for northern bobwhite quail that can be used to enhance management of the species. J. WILDL. MANAGE. 53(1):1-6 Although research on northern bobwhite quail began in the 1920s (Stoddard 1931, Errington 1933), studies of quail survival have been limited. Sound management requires good estimates of mortality rates. Mortality for hunted species can be estimated from band recovery data using models prepared by Brownie et al. (1985). These models also provide band recovery rate estimates. Harvest rate is easily obtained if the reporting rate of bands is known. Total kill estimates follow from harvest estimates if an estimate of crippling loss is available. With these data managers can partition hunting and natural (nonhunting) mortality. A recent series of papers questions whether hunting and natural mortality are additive (Anderson and Burnham 1976, Anderson et al. 1982, Nichols and Hines 1983, Burnham and Anderson 1984, Burnham et al. 1984, Nichols et al. 1984). Most of this work applies to waterfowl, particularly mallards (Anas platyrhynchos), for which the most band recovery data are available. We report the results of a long-term bandrecovery study of bobwhite quail at Tall Timbers Research Station, Leon County, Florida. We obtained survival estimates and test the additive and compensatory mortality hypotheses (Anderson et al. 1982). W. L. Cornelius assisted with computing and J. D. Nichols reviewed an earlier draft of the manuscript. We thank present and past coworkers and many biologists and volunteers, especially wildlife technician students at Abraham Baldwin Agricultural College, for their help. This study was supported in part by Tall Timbers Research Station, Tallahassee, Florida and by an appropriation from the Congress of the United States. Funds were administered and research coordinated under the Federal Aid in Wildlife Restoration Act and through the U.S. Fish and Wildlife Service.

Landscape Change in the Southern Piedmont: Challenges, Solutions, and Uncertainty Across Scales

The southern Piedmont of the southeastern United States epitomizes the complex and seemingly intractable problems and hard decisions that result from uncontrolled urban and suburban sprawl. Here we consider three recurrent themes in complicated problems involving complex systems: (1) scale dependencies and cross-scale, often nonlinear relationships; (2) resilience, in particular the potential for complex systems to move to alternate stable states with decreased ecological and/or economic value; and (3) uncertainty in the ability to understand and predict outcomes, perhaps particularly those that occur as a result of human impacts. We consider these issues in the context of landscape-level decision making, using as an example water resources and lotic systems in the Piedmont region of the southeastern United States.

Adaptive management in the U.S. National Wildlife Refuge System: Science-management partnerships for conservation delivery

Adaptive management is an approach to recurrent decision making in which uncertainty about the decision is reduced over time through comparison of outcomes predicted by competing models against observed values of those outcomes. The National Wildlife Refuge System (NWRS) of the U.S. Fish and Wildlife Service is a large land management program charged with making natural resource management decisions, which often are made under considerable uncertainty, severe operational constraints, and conditions that limit ability to precisely carry out actions as intended. The NWRS presents outstanding opportunities for the application of adaptive management, but also difficult challenges. We describe two cooperative programs between the Fish and Wildlife Service and the U.S. Geological Survey to implement adaptive management at scales ranging from small, single refuge applications to large, multi-refuge, multi-region projects. Our experience to date suggests three important attributes common to successful implementation: a vigorous multi-partner collaboration, practical and informative decision framework components, and a sustained commitment to the process. Administrators in both agencies should consider these attributes when developing programs to promote the use and acceptance of adaptive management in the NWRS.

Evaluation of the landscape surrounding northern bobwhite nest sites : A multiscale analysis

Abstract Implementation of the Conservation Reserve Program (CRP) altered the interspersion and abundance of patches of different land-cover types in landscapes of the southeastern United States. Because northern bobwhites (Colinus virginianus) are experiencing significant population declines throughout most of their range, including the Southeast, it is critical to understand the impacts of landscape-scale changes in habitat on their reproductive rates. Our objective was to identify components of landscape structure important in predicting nest site selection by bobwhites at different spatial scales in the Upper Coastal Plain of Georgia. We used a Geographic Information System (GIS) and spatial analysis software to calculate metrics of landscape structure near bobwhite nest sites. Logistic regression was used to model the relationship of nest sites to structure within the surrounding landscape at 4 spatial scales. We found that patch density and open-canopy planted pine were consistently important predictor variables at multiple scales, and other variables were important at various scales. The density of different patch types could be increased by thinning rows of pines in large monotypic stands of closed-canopy planted pine stands. Thinning and creating openings in CRP pine plantations should provide increased nesting opportunities for bobwhites. We interpret the support for other variables in our analysis as an indication that various patch configuration lead to different combinations of landscape structure that provide an acceptable range of habitat conditions for bobwhites.

Evaluating release alternatives for a long-lived bird species under uncertainty about long-term demographic rates

The release of animals to reestablish an extirpated population is a decision problem that is often attended by considerable uncertainty about the probability of success. Annual releases of captive-reared juvenile Whooping Cranes (Grus americana) were begun in 1993 in central Florida, USA, to establish a breeding, non-migratory population. Over a 12-year period, 286 birds were released, but by 2004, the introduced flock had produced only four wild-fledged birds. Consequently, releases were halted over managers’ concerns about the performance of the released flock and uncertainty about the efficacy of further releases. We used data on marked, released birds to develop predictive models for addressing whether releases should be resumed, and if so, under what schedule. To examine the outcome of different release scenarios, we simulated the survival and productivity of individual female birds under a baseline model that recognized age and breeding-class structure and which incorporated empirically estimated stochastic elements. As data on wild-fledged birds from captive-reared parents were sparse, a key uncertainty that confronts release decision-making is whether captive-reared birds and their offspring share the same vital rates. Therefore, we used data on the only population of wild Whooping Cranes in existence to construct two alternatives to the baseline model. The probability of population persistence was highly sensitive to the choice of these three models. Under the baseline model, extirpation of the population was nearly certain under any scenario of resumed releases. In contrast, the model based on estimates from wild birds projected a high probability of persistence under any release scenario, including cessation of releases. Therefore, belief in either of these models suggests that further releases are an ineffective use of resources. In the third model, which simulated a population Allee effect, population persistence was sensitive to the release decision: high persistence probability was achieved only through the release of more birds, whereas extirpation was highly probable with cessation of releases. Despite substantial investment of time and effort in the release program, evidence collected to date does not favor one model over another; therefore, any decision about further releases must be made under considerable biological uncertainty. However, given an assignment of credibility weight to each model, a best, informed decision about releases can be made under uncertainty. Furthermore, if managers can periodically revisit the release decision and collect monitoring data to further inform the models, then managers have a basis for confronting uncertainty and adaptively managing releases through time.

ECOLOGY OF HELMINTH PARASITISM IN BOBWHITES FROM NORTHERN FLORIDA

Examination of 700 northern bobwhites (Colinus virginianus), 50 each February from 1971 through 1984, from Tall Timbers Research Station, Leon County, Florida, disclosed 15 species of helminth parasites. Nine species (Raillietina cesticillus, R. colinia, Aproctella stoddardi, Cheilospirura spinosa, Cyrnea colini, Dispharynx nasuta, Heterakis isolonche, Tetrameres pattersoni, and Trichostrongylus tenuis) generally were found on an annual basis and were considered characteristic components of the helminth fauna. Infrequently found species were Brachylecithum nanum, Rhabdometra odiosa, Capillaria sp., Gongylonema ingluvicola, H. gallinarum, and Oxyspirura matogrosensis. Intensities of C. colini and H. isolonche differed among host sex and age classes, and prevalences and/or intensities of A. stoddardi, C. spinosa, T. pattersoni, and T. tenuis differed between host age classes. Prevalences and/or abundances of seven species (R. cesticillus, R. colinia, C. spinosa, C. colini, H. isolonche, T. pattersoni, and T. tenuis) varied with bobwhite density, apparently because bobwhites were either the primary or only definitive host on the area. Two species (A. stoddardi and D. nasuta) did not vary with bobwhite density, apparently due to the buffering effect of a broad range of definitive hosts on the area. Prevalences and/or intensities of R. colinia, C. spinosa, and T. tenuis differed with agricultural fields status (cultivated versus fallow) suggesting that land use and its attendant habitat changes influenced transmission of these species. The occurrence of C. spinosa and T. pattersoni in individual bobwhites was not independent and was attributed to utilization of the same species of grasshoppers as intermediate hosts. Localized tissue damage and inflammation were associated with A. stoddardi, D. nasuta, C. spinosa, C. colini and T. pattersoni. Decreases in body weight in juvenile bobwhites were associated with increasing intensities of H. isolonche and T. tenuis. The observed relationships to bobwhite density and other variables are discussed with regard to known aspects of life histories of the nine most common species.

SourceS of Variation in Detection of WaDing BirDS from aerial SurVeyS in the floriDa eVerglaDeS

Abstract We conducted dual-observer trials to estimate detection probabilities (probability that a group that is present and available is detected) for fixed-wing aerial surveys of wading birds in the Everglades system, Florida. Detection probability ranged from <0.2 to ~0.75 and varied according to species, group size, observer, and the observers position in the aircraft (front or rear seat). Aerial-survey simulations indicated that incomplete detection can have a substantial effect on assessment of population trends, particularly over relatively short intervals (≤3 years) and small annual changes in population size (≤3%). We conclude that detection bias is an important consideration for interpreting observations from aerial surveys of wading birds, potentially limiting the use of these data for comparative purposes and trend analyses. We recommend that workers conducting aerial surveys for wading birds endeavor to reduce observer and other controllable sources of detection bias and account for uncontrollable sources through incorporation of dual-observer or other calibration methods as part of survey design (e.g., using double sampling).

Effects of Human Activity on Behavior of Breeding American Oystercatchers, Cumberland Island National Seashore, Georgia, USA

Abstract Increased human use of coastal areas threatens the United States population of American Oystercatchers (Haematopus palliatus), a species of special concern. Biologists often attribute its low numbers and reproductive success to human disturbance, but the mechanism by which human presence reduces reproductive success is not well understood. During the 2003 and 2004 breeding seasons, 32 nesting attempts of American Oystercatchers were studied on Cumberland Island National Seashore (CINS). Behavior was examined with and without human activity in the area to determine how human activity affected behavior. The oystercatchers’ behavioral responses (proportion time) were analyzed with and without human or intraspecific disturbances using mixed models regression analysis. Proportions of time human activities were present (≤300 m from oystercatchers) during observations averaged 0.14 (N = 32, 95% CI = 0.08-0.20). During incubation, pedestrian activity near (≤137 m) oystercatchers reduced the frequency of occurrence of reproductive behavior, but pedestrian activity far (138-300 m) from oystercatchers had no effect. Vehicular and boat activities (≤300 m) had minimal effects on behavior during incubation. During brood rearing, an effect of pedestrian activity near oystercatchers was not evident; however, pedestrian activity far from oystercatchers increased the frequency of reproductive behavior. Vehicular and boat activity had no effects on behavior during brood rearing. Of 32 nesting attempts, two failed (<10%) because of human disturbance and were located in areas of greater human activity (south end). Managers on CINS should minimize pedestrian activity near nests (≤137 m) during incubation. During brood rearing, protection from pedestrian activity should be increased, when possible, to >137 m and vehicular activity should be minimized at current levels or less.

Forest management decisions for wildlife objectives : system resolution and optimality

Abstract Managers of forest wildlife populations make recurring management decisions based on incomplete knowledge of system states. For example, animal population estimates may ignore spatial structure that may influence population viability. We built a spatially-explicit model for a population of birds in a forested landscape. Rates of bird population growth within forest compartments and rates of bird dispersal among compartments were functions of stand age and basal area, compartment population size, and inter-compartment distance. Stand characteristics were imbedded in a dynamic model and assumed perfectly observable and under the complete control of managers. We constructed a genetic algorithm to search for the schedule and spatial distribution of silviculture to maximize total bird abundance at the end of a fixed planning horizon, under combinations of initial habitat and population distribution. We also found policies for a smaller set of population distributions that a manager may only presume to occur (e.g. birds equally distributed among stands), as when managers are only able to observe abundance and not spatial distribution. We investigated the effect of this loss of system resolution on optimality by examining differences in projected population sizes under the two types of policies. That is, we used the set of ‘presumed-state’ policies to project population size from each true initial system state, then we compared these to projections under the best policy for that state. For the planning horizon that we considered, loss in optimality was highly dependent on initial habitat state and on choice of presumed population distribution. Generally, loss in optimality and species extinction rate were both greater for habitat states that were initially poor than initially favorable. For some initial habitat states, population projections based on policies for presumed states often exceeded objective function values for known-state policies, suggesting that the genetic algorithm frequently fell short of finding bona fide optima.

Models of mass growth for 3 North American cougar populations

Previous studies of cougar (Felis concolor) physiology and population dynamics relied on growth curves of cougars obtained from diverse locations and under various rearing conditions. We were concerned about potential biases in studies that make but do not test the implicit assumption of homogeneity of growth characteristics among collection sites. Thus, we compared body masses of wild cougars from populations in Florida (F. c. coryi), Nevada (F. c. kaibalensis), and California (F. c. californica). We modeled mass as a nonlinear Richards function of age for each sex and population demographic group