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K.P. Burnham

Publications and source records attributed to K.P. Burnham.

36 records · Page 2Linked to original sources
USGS1999

A closure test for time-specific capture-recapture data

The assumption of demographic closure in the analysis of capture-recapture data under closed-population models is of fundamental importance. Yet, little progress has been made in the development of omnibus tests of the closure assumption. We present a closure test for time-specific data that, in principle, tests the null hypothesis of closed-population model M(t) against the open-population Jolly-Seber model as a specific alternative. This test is chi-square, and can be decomposed into informative components that can be interpreted to determine the nature of closure violations. The test is most sensitive to permanent emigration and least sensitive to temporary emigration, and is of intermediate sensitivity to permanent or temporary immigration. This test is a versatile tool for testing the assumption of demographic closure in the analysis of capture-recapture data.

Environmental and Ecological Statistics↗
USGS1979

Robust estimation of population size when capture probabilities vary among animals

A model is given for multiple recapture studies on closed populations which allows capture probabilities to vary among individuals. The capture probability of each individual is assumed to be constant over time. Based on this model we give a nonparametric estimation procedure for population size. The estimator involves selecting one of a sequence of estimator which are each linear combinations of the capture frequencies. The individual estimators are derived from the generalized jackknife method. We also give a goodness of fit test for the model's assumption that individual capture probabilities do not change during the study. The robustness of the estimation procedure is investigated with a simulation study. By virtue of this study, and the theoretical nature of the estimator, it is judged to be robust to moderate variations in individual capture probabilities which may occur in commonly used short-term livetrapping studies.

Ecology↗
USGS1979

Nonparametric estimation of plant density by the distance method

A relation between the plant density and the probability density function of the nearest neighbor distance (squared) from a random point is established under fairly broad conditions. Based upon this relationship, a nonparametric estimator for the plant density is developed and presented in terms of order statistics. Consistency and asymptotic normality of the estimator are discussed. An interval estimator for the density is obtained. The modifications of this estimator and its variance are given when the distribution is truncated. Simulation results are presented for regular, random and aggregated populations to illustrate the nonparametric estimator and its variance. A numerical example from field data is given. Merits and deficiencies of the estimator are discussed with regard to its robustness and variance.

Biometrics↗
USGS1978

Estimation of the size of a closed population when capture probabilities vary among animals

A model which allows capture probabilities to vary by individuals is introduced for multiple recapture studies n closed populations. The set of individual capture probabilities is modelled as a random sample from an arbitrary probability distribution over the unit interval. We show that the capture frequencies are a sufficient statistic. A nonparametric estimator of population size is developed based on the generalized jackknife; this estimator is found to be a linear combination of the capture frequencies. Finally, tests of underlying assumptions are presented.

Biometrika↗
USGS1978

A log-linear model approach to estimation of population size using the line-transect sampling method

The technique of estimating wildlife population size and density using the belt or line-transect sampling method has been used in many past projects, such as the estimation of density of waterfowl nestling sites in marshes, and is being used currently in such areas as the assessment of Pacific porpoise stocks in regions of tuna fishing activity. A mathematical framework for line-transect methodology has only emerged in the last 5 yr. In the present article, we extend this mathematical framework to a line-transect estimator based upon a log-linear model approach.

Ecology↗
USGS1976

Mathematical models for non-parametric inferences from line transect data

A general mathematical theory of line transects is developed which supplies a framework for nonparametric density estimation based on either right angle or sighting distances. The probability of observing a point given its right angle distance (y) from the line is generalized to an arbitrary function g(y). Given only that g(0) = 1, it is shown there are nonparametric approaches to density estimation using the observed right angle distances. The model is then generalized to include sighting distances (r). Let f(y I r) be the conditional distribution of right angle distance given sighting distance. It is shown that nonparametric estimation based only on sighting distances requires we know the transformation of r given by f(0 I r).

Biometrics↗
USGS1976

A reward band study of mallards to estimate band reporting rates

Reward bands ($10) were placed on 2,122 hatching-year mallards ( Anas platyrhynchos ), and an additional 11,490 received conventional bands (controls) to estimate band reporting rates. An analysis of band recoveries indicated that the reporting rate was dependent primarily upon three factors: (1) the distance banded birds were recovered from the banding site, (2) band collecting activities of conservation agencies (usually near banding sites), and ( 3) the intensity of banding effort in the region (frequency of banded birds in the population of the region). Reporting rates were uniformly depressed near the banding sites, but they showed an east-west cline at distances greater than 80 km from the banding sites. The reporting rate was highest in the west. Limited data on historical band reporting rates were compiled. Recommendations are given for adjusting band recoveries to account for the nonreporting of bands for 1957-73.

Journal of Wildlife Management↗