In this paper kernel methods for the nonparametric estimation of the utilization distribution from a random sample of locational observations made on an animal in its home range are described. They are of flexible form, thus can be used where simple parametric models are found to be inappropriate or difficult to specify. Two examples are given to illustrate the fixed and adaptive kernel approaches in data analysis and to compare the methods. Various choices for the smoothing parameter used in kernel methods are discussed. Since kernel methods give alternative approaches to the Anderson (1982) Fourier transform methods, some comparisons are made.

Kernel methods for estimating the utilization distribution in home-range studies

Ninety-three papers on home-range analysis using radio-tracking data were reviewed; these papers were found in a literature search of 18 of the major journals likely to include such papers, published in the 5-year period to the end of 1988. The review showed that even 25 years after the first radio-tracking studies, in the majority of papers there was still insufficient attention given to accurate and sufficient data collection, and to using appropriate and sophisticated analytical techniques to assess home-range size and configuration. This paper is designed to help people undertaking a radio-tracking study to avoid some of the most common pitfalls. It is based on some of the problems we have experienced studying several species of larger mammals. We use our collective experience to produce a guide on how to plan a radio-tracking study, to highlight some of the potential problems in designing the study and collecting the data, and to identify some of the difficulties that may be encountered during the analytical stages. The advantages and disadvantages of the most frequently used methods of home-range analysis are discussed and methods for determining the minimum number of radio-fixes and techniques for adjusting inadequate sample sizes are described, as are the problems that may be caused by autocorrelated data.

Home‐range analysis using radio‐tracking data–a review of problems and techniques particularly as applied to the study of mammals

(1) Animals generally use space disproportionately within the boundaries of their home range. Areas receiving concentrated use by resident animals can be termed core areas. Identifying these core areas is an important part of understanding the ecological factors that determine use. (2) Comparison of the observed space-use pattern with that expected from a uniform pattern of use is our basis for defining core areas. The difference in ordered cumulative distribution functions can be tested using a one-sided goodness-of-fit procedure. Core areas are delineated by enscribing those areas within the home range where use exceeds that expected from a uniform distribution. (3) This method of estimating core areas is illustrated with a hypothetical data set and applied to radio-telemetry locations of a black bear (Ursus americanus, Pallas). The bear used two distinct core areas, which enclosed 34% of the total home range and included 76% of the animal locations. (4) Patterns of core area use are demonstrated for male western tanagers (Piranga ludoviciana, Wilson). Although 90% home range boundaries overlap, core areas for four adjacent males are shown to closely resemble exclusive-use territories. (5) Interspecific use of core areas of western tanagers and chipping sparrows (Spizella passerina, Bechstein) are compared. Core areas for chipping sparrows tended to be a larger proportion of the home range and intensity of core area use was greater for western tanagers. (6) The size and location of core areas depend on the method of determination of home range size. Alternative home range methods may have a substantial influence on the estimation of core areas due to differences in the estimated home range boundary and underlying use distribution.

https://www.jstor.org/stable/pdfplus/4373.pdf

Identifying areas of concentrated use within the home range

A new technique for estimating home range size from a sequence of independent observations of animal positions is introduced. This method describes home range in a probabilistic sense, makes no assumption about the underlying distribution, and therefore is nonparametric. The procedure is based upon an existing nonparametric technique for density estimation which uses the Fourier transform (Tarter and Kronmal 1970). A comparison is made with two commonly used methods; the minimum convex polygon method (Southwood 1966) and bivariate normal method (Jennrich and Turner 1969), as well as another recent nonparametric method developed by Ford and Krumme (1979). All these methods have certain problems, making none of them suitable for every situation. The trade—offs among these methods and some fundamental limitations of home range estimation are discussed. Evidence is given which indicates that in some situations the proposed method is preferable to earlier methods.

The Home Range: A New Nonparametric Estimation Technique

/pdf/managing-vertebrate-pests-foxes-qcmqks0uui.pdf

Managing vertebrate pests: foxes.

Previously used methods to analyze radio tracking data have not generally taken advantage of all the information associated with location fixes Most early analyses were preoccupied with size and shape of home range Analysis strategies with options determined by study objectives, type of data and species-specific variables are described Descriptions can include cartographical, graphic and tabular depictions of distributions for spatial, habitat, and activity type utilization, direction and orientation as well as interaction potential measures A sample set of data from a red fox radio tracking study was used to demonstrate methods of analysis Analysis was performed interactively, which permitted the researcher to interrogate the data base with few inherent assumptions Computer algorithms for measuring area and depicting borders of home ranges were compared for consistency, sensitivity and richness for biological implications Two methods employing cell frequency counts were found to be useful for investigating the internal anatomy of home ranges Emphasis is placed on describing approaches to answering questions on how animals use their home areas rather than the computer program package developed A review of home range analysis and literature is also included

D.R. Voigt

Papers

Strategies for Analyzing Radio Tracking Data