scholarly journals Size of Territories and Home Ranges of Male Western Yellow-breasted Chats (Icteria virens auricollis) in British Columbia

2012 ◽  
Vol 126 (2) ◽  
pp. 152 ◽  
Author(s):  
René McKibbin ◽  
Christine A. Bishop
Keyword(s):  
British Columbia ◽  
Density Estimation ◽  
Statistical Difference ◽  
Radio Telemetry ◽  
Kernel Density ◽  
Home Ranges ◽  
Radio Tracking ◽  
Icteria Virens ◽  
Radio Transmitters ◽  
The Mean

During 2005 and 2006, radio-transmitters were fitted to a total of 11 male Western Yellow-breasted Chats, Icteria virens auricollis, in the southern Okanagan River valley, British Columbia, to compare the area used, as detected by radio-telemetry and as defined by mapped observations of breeding males singing and perching. Data were only collected for 5 males. For 2005 and 2006, the 95% kernel density estimation (KDE) revealed that mean area used by male Western Yellow-breasted Chats, as determined by radio-tracking (n = 5), was 1.16 ha, whereas the mean area as defined by observations of breeding males singing and perching was 0.62 ha (no statistical difference). Our hypothesis that the area determined by radio-tracking would be significantly larger than the area defined by observations of males singing and perching was rejected, but the area determined by radio-tracking was almost twice the area defined by observations of breeding males singing and perching.

scholarly journals Transmetric Density Estimation

2016 ◽  
Vol 5 (2) ◽  
pp. 35
Author(s):  
Sigve Hovda
Keyword(s):  
Density Estimation ◽  
Kernel Density Estimation ◽  
Kernel Density ◽  
Convergence Order ◽  
Graphical Display ◽  
Mean Integrated Squared Error ◽  
Squared Error ◽  
Integrated Squared Error ◽  
The Mean ◽  
Convergence Orders

<div>A transmetric is a generalization of a metric that is tailored to properties needed in kernel density estimation.  Using transmetrics in kernel density estimation is an intuitive way to make assumptions on the kernel of the distribution to improve convergence orders and to reduce the number of dimensions in the graphical display.  This framework is required for discussing the estimators that are suggested by Hovda (2014).</div><div> </div><div>Asymptotic arguments for the bias and the mean integrated squared error is difficult in the general case, but some results are given when the transmetric is of the type defined in Hovda (2014).  An important contribution of this paper is that the convergence order can be as high as $4/5$, regardless of the number of dimensions.</div>

scholarly journals Population-level inference for home-range areas

2021 ◽  
Author(s):  
Christen Herbert Fleming ◽  
Iman Deznabi ◽  
Shauhin Alavi ◽  
Margaret C. Crofoot ◽  
Ben T. Hirsch ◽  
...  
Keyword(s):  
Home Range ◽  
Density Estimation ◽  
Kernel Density Estimation ◽  
Kernel Density ◽  
Population Level ◽  
Home Ranges ◽  
Tracking Data ◽  
Temporal Autocorrelation ◽  
Time Space ◽  
Minimal Convex

· Home-range estimates are a common product of animal tracking data, as each range informs on the area needed by a given individual. Population-level inference on home-range areas—where multiple individual home-ranges are considered to be sampled from a population—is also important to evaluate changes over time, space, or covariates, such as habitat quality or fragmentation, and for comparative analyses of species averages. Population-level home-range parameters have traditionally been estimated by first assuming that the input tracking data were sampled independently when calculating home ranges via conventional kernel density estimation (KDE) or minimal convex polygon (MCP) methods, and then assuming that those individual home ranges were measured exactly when calculating the population-level estimates. This conventional approach does not account for the temporal autocorrelation that is inherent in modern tracking data, nor for the uncertainties of each individual home-range estimate, which are often large and heterogeneous. · Here, we introduce a statistically and computationally efficient framework for the population-level analysis of home-range areas, based on autocorrelated kernel density estimation (AKDE), that can account for variable temporal autocorrelation and estimation uncertainty. · We apply our method to empirical examples on lowland tapir (Tapirus terrestris), kinkajou (Potos flavus), white‐nosed coati (Nasua narica), white-faced capuchin monkey (Cebus capucinus), and spider monkey (Ateles geoffroyi), and quantify differences between species, environments, and sexes. · Our approach allows researchers to more accurately compare different populations with different movement behaviors or sampling schedules, while retaining statistical precision and power when individual home-range uncertainties vary. Finally, we emphasize the estimation of effect sizes when comparing populations, rather than mere significance tests.

The effects of translocation on the spatial ecology of tiger snakes (Notechis scutatus) in a suburban landscape

2005 ◽  
Vol 32 (2) ◽  
pp. 165 ◽  
Author(s):  
H. Butler ◽  
B. Malone ◽  
N. Clemann
Keyword(s):  
Spatial Ecology ◽  
Private Property ◽  
Radio Telemetry ◽  
Home Ranges ◽  
Residential Areas ◽  
Perceived Risks ◽  
Radio Transmitters ◽  
The Impact ◽  
Suburban Landscape ◽  
Very High

In many suburban parts of Australia the removal of snakes from private property by licenced snake catchers is employed to mitigate perceived risks to humans and their pets. The number of snakes translocated around greater Melbourne, Victoria, each year can be very high (at least many hundreds). However, the effects of translocation on the behaviour and welfare of individual snakes, and the impact on existing snake populations at release sites are unknown. We used radio-telemetry of ‘resident’ and translocated snakes to investigate the consequences of translocation on the spatial ecology of tiger snakes (Notechis scutatus) in a suburban parkland near Melbourne. Fourteen snakes (two female and four male residents, and four female and four male translocated snakes) implanted with radio-transmitters were tracked between spring 2002 and autumn 2003. Translocated snakes exhibited home ranges ~6 times larger than those of residents, although each group maintained core ranges of similar size. Translocated snakes travelled longer distances and were often located in residential areas adjacent to the park, whereas resident snakes were never located outside of the park.

Radio-tagging and tracking of translocated trout cod (Maccullochella macquariensis: Percichthyidae) in an upland river

2009 ◽  
Vol 60 (4) ◽  
pp. 346 ◽  
Author(s):  
B. C. Ebner ◽  
L. Johnston ◽  
M. Lintermans
Keyword(s):  
Spatial Ecology ◽  
Effective Means ◽  
Release Site ◽  
Early Morning ◽  
Home Ranges ◽  
Radio Tracking ◽  
Natural Habitats ◽  
Radio Transmitters ◽  
Radio Tagging ◽  
Species Rarity

Radio-tracking provides an effective means of studying the spatial ecology of threatened fishes where almost inaccessible habitats and species rarity render conventional mark–recapture methods impractical. Initially, validation of an effective radio-tagging method is required; in the present study, an aquaria trial based on nine hatchery-reared, adult male Maccullochella maquariensis (Percichthyidae) was conducted. Fish resumed feeding within days of being internally implanted with a radio-tag, and tag rejection was not observed (0%, n = 9) based on a 2-month observational period. Following release into an upland stream, individual-specific movements resulted in upstream (n = 1) and downstream (n = 6) dispersal as well as fidelity to the release site (n = 2) at the completion of the study. Individuals established small home-ranges (mean length of river used by an individual per diel period ranged from 47 to 292 m) and were most active in the early morning and evening (n = 6). Complete survivorship of individuals bearing active radio-transmitters (n = 8) was recorded up until 4 months after release. However, an estimated zero or one individual was alive when the last active radio-tag expired 11 months after release (n = 8). The present study highlights the use of radio-tracking in monitoring the dispersal and survivorship of small numbers of hatchery-reared threatened fish released into natural habitats as part of species re-introduction programs.

Movements, Activity Patterns and Habitat Use of Feral Pigs (Sus scrofa) in a Tropical Habitat

1997 ◽  
Vol 24 (1) ◽  
pp. 77 ◽  
Author(s):  
Peter Caley
Keyword(s):  
Habitat Use ◽  
Riparian Vegetation ◽  
Radio Telemetry ◽  
Activity Patterns ◽  
Early Morning ◽  
Home Range Size ◽  
Home Ranges ◽  
Feral Pigs ◽  
Live Trapping ◽  
The Mean

Movements, activity patterns and habitat use of feral pigs were studied in a tropical woodland habitat by radio-telemetry, live-trapping and hunter returns. The mean aggregate home-range size was 33.5 km2 for boars and 24.1 km2 for sows. Feral pigs were rather sedentary, with no tendency to disperse great distances from their initial home ranges. Pigs were most active at night, with peaks of activity in the late afternoon and early morning. Pigs preferentially used the riparian vegetation strip bordering major rivers, and grain crops, when available. The implications for the management of pigs are discussed.

Use of stream and river habitats by the platypus, Ornithorhynchus anatinus, in an urban fringe environment

1998 ◽  
Vol 46 (3) ◽  
pp. 267 ◽  
Author(s):  
M. Serena ◽  
J. L. Thomas ◽  
G. A. Williams ◽  
R. C. E. Officer
Keyword(s):  
Radio Telemetry ◽  
Central Business District ◽  
Home Ranges ◽  
Horizontal Distance ◽  
North East ◽  
Ornithorhynchus Anatinus ◽  
Drainage Channels ◽  
The Mean ◽  
Business District ◽  
Yarra River

Radio-telemetry was used to monitor movements and burrow usage by O. anatinus living in the Yarra River catchment, about 20 km east-north-east of the central business district of Melbourne, Victoria. The home ranges of six adult or subadult animals were 2.9–7.3 km (mean ± s.d. = 4.6 ± 1.6 km) long, with individuals travelling up to 10.4 km (males) and 4.0 km (females) in a single overnight period. The mean home-range length of adult/subadult animals was significantly greater than that of juveniles (1.4–1.7 km, mean ± s.d. = 1.55 ± 0.2 km, n = 2). The animals utilised two drainage channels as well as 11.8 km of natural waterways, including the Yarra River (5 km), Mullum Mullum Creek (4 km) and Diamond Creek (2.8 km). Several animals travelled repeatedly below one-lane and two-lane bridges, confirming that these structures are not inherent barriers to platypus movement. In total, 57 platypus burrows were described, including 26 along the river, 29 along the creeks and 2 along drains. The horizontal distance from the water’s edge to burrow chambers was 0.4–3.7 m (mean ± s.d. = 1.5 ± 0.9 m, n = 41), with burrows found only in banks extending ≥ 0.5 m above the water. Platypus burrows occurred significantly more often than expected along undercut banks and in association with moderate-to-dense vegetation overhanging the water, and significantly less often at sites where banks had a convex profile at water level. As well, the amount of cover provided along the bank by shrubs/small trees and the ground layer of vegetation was significantly greater than expected at platypus burrows along the river. These attributes are believed to help conceal burrow entrances from predators as well as reduce burrow damage through erosion.

Home range, movement and habitat utilisation of the Carpentarian rock-rat (Zyzomys palatalis) in an isolated habitat patch

2004 ◽  
Vol 31 (3) ◽  
pp. 327 ◽  
Author(s):  
Helen Puckey ◽  
Milton Lewis ◽  
David Hooper ◽  
Carrie Michell
Keyword(s):  
Home Range ◽  
Radio Telemetry ◽  
Central Area ◽  
Limited Resource ◽  
Home Ranges ◽  
Habitat Patch ◽  
Minimum Convex Polygon ◽  
Significant Difference ◽  
Core Areas ◽  
The Mean

Radio-telemetry was used to examine the home range, movement and habitat utilisation of the critically endangered Carpentarian rock-rat (Zyzomys palatalis) in an isolated habitat patch in the Gulf of Carpentaria hinterland over a 13-month period. Two home-range estimators were used in the study, (i) minimum convex polygon (MCP) and (ii) fixed Kernel (KL), the latter also being used to estimate core areas of activity. Based on a total sample size of 21 individuals, the mean MCP home range was 11 165 m2, similar to the mean KL home range of 10 687 m2. Core areas were, on average, 11.9% of the KL home-range estimate. There was no significant difference in the size of home range or core area of males and females. Juveniles had a significantly smaller home range than adults. Home ranges and, to a lesser degree, core areas were non-exclusive, with multiple areas of overlap (averaging 41% and 38% respectively) within and between all age and gender categories, but especially between males and between juveniles. Movement frequencies showed that animals made many short forays in a central area close to the arithmetic home-range mean and far fewer long forays of distances greater than 100 m from the central area. The spatial and temporal activity of Z. palatalis was concentrated in, but not confined to, the 'valley' and 'slope' habitats, with fewer movements of rats onto the surrounding 'plateau'. Resource selection analyses showed that Z. palatalis tended to prefer valley and slope habitats over the plateau and that the proportion of point locations was significantly higher for adults in the slope habitat and for juveniles in the valley habitat. Most home ranges were centred on the ecotone between these two habitat types. Although isolated and spatially limited, these habitat patches provide high-quality resources for dense populations of Z. palatalis. This study exemplifies a species' attempt to make efficient use of a limited resource in an otherwise hostile environment. Even small declines in habitat area or quality due to their vulnerability to fire would impact upon many animals.

scholarly journals Properties of Transmetric Density Estimation

2016 ◽  
Vol 5 (3) ◽  
pp. 63
Author(s):  
Sigve Hovda
Keyword(s):  
Density Estimation ◽  
Kernel Density ◽  
Density Estimator ◽  
Unified Approach ◽  
Squared Error ◽  
Special Cases ◽  
Integrated Squared Error ◽  
The Common ◽  
The Mean ◽  
Convergence Orders

Transmetric density estimation is a generalization of kernel density estimation that is proposed in Hovda(2014) and Hovda (2016), This framework involves the possibility of making assumptions on the kernel of the distribution to improve convergence orders and to reduce the number of dimensions in the graphical display.  In this paper we show that several state-of-the-art nonparametric, semiparametric and even parametric methods are special cases of this formulation, meaning that there is a unified approach. Moreover, it is shown that parameters can be trained using unbiased cross-validation.  When parameter estimation is included, the mean integrated squared error of the transmetric density estimator is lower than for the common kernel density estimator, when the number of dimensions is larger than two.

scholarly journals Size of home range of Tengmalm’s owl (Aegolius funereus) males during breeding season assessed by radio-telemetry in the Jizera Mountains, Czechia

2018 ◽  
Vol 12 (1) ◽  
pp. 1-7
Author(s):  
Marek Kouba ◽  
Václav Tomášek
Keyword(s):  
Home Range ◽  
Breeding Season ◽  
Radio Telemetry ◽  
Home Range Size ◽  
Range Size ◽  
Time Interval ◽  
Home Ranges ◽  
Aegolius Funereus ◽  
The Mean ◽  
Tengmalm's Owl

Abstract Animal home ranges are typically characterized by their size, shape and a given time interval and can be affected by many different biotic and abiotic factors. Understanding of animal movements and assessing the size of their home ranges are essential topics in ecology and necessary for effective species protection, especially concerning birds of prey. Using radio-telemetry (VHF; 2.1 g tail-mounted tags) we studied the movements of two Tengmalm’s owl (Aegolius funereus) males during the breeding season 2008 in a mountain area of Central Europe (the Czech Republic, the Jizera Mountains: 50˚ 50’ N, 15˚ 16’ E). We determined their average nocturnal hunting and diurnal roosting home range sizes. The mean hunting home range size calculated according to the 90% fixed kernel density estimator was 251.1 ± 43.2 ha (± SD). The mean roosting home range size calculated according to the 100% minimum convex polygon method was 57.9 ± 15.8 ha (± SD). The sizes of hunting home ranges during breeding in this study coincide with those previously reported by other studies focusing on Tengmalm’s owl males. However, we found the roosting home ranges were smaller in size compared to those previously reported. This result was most probably connected with different habitat structure in our study area, which was severally damaged by air-pollution in the past, thus probably offering fewer suitable hiding-places, for instance from predators. We found the roosting locations were concentrated in the oldest and densest Norway spruce forest patches. We emphasize that these parts of forest stands require the highest possible protection in our study area.

scholarly journals Optimal Bandwidth Selection for Kernel Density Functionals Estimation

2015 ◽  
Vol 2015 ◽  
pp. 1-21 ◽  
Author(s):  
Su Chen
Keyword(s):  
Density Estimation ◽  
Bandwidth Selection ◽  
Kernel Density ◽  
Least Square ◽  
Density Functionals ◽  
Selection Methods ◽  
Optimal Bandwidth ◽  
Location Parameters ◽  
The Mean ◽  
Selection For

The choice of bandwidth is crucial to the kernel density estimation (KDE) and kernel based regression. Various bandwidth selection methods for KDE and local least square regression have been developed in the past decade. It has been known that scale and location parameters are proportional to density functionals∫γ(x)f2(x)dxwith appropriate choice ofγ(x)and furthermore equality of scale and location tests can be transformed to comparisons of the density functionals among populations.∫γ(x)f2(x)dxcan be estimated nonparametrically via kernel density functionals estimation (KDFE). However, the optimal bandwidth selection for KDFE of∫γ(x)f2(x)dxhas not been examined. We propose a method to select the optimal bandwidth for the KDFE. The idea underlying this method is to search for the optimal bandwidth by minimizing the mean square error (MSE) of the KDFE. Two main practical bandwidth selection techniques for the KDFE of∫γ(x)f2(x)dxare provided: Normal scale bandwidth selection (namely, “Rule of Thumb”) and direct plug-in bandwidth selection. Simulation studies display that our proposed bandwidth selection methods are superior to existing density estimation bandwidth selection methods in estimating density functionals.

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