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Improving the analysis of movement data from marked individuals through explicit estimation of observer heterogeneity

Korner-Nievergelt, F. and Sauter, A. and Atkinson, P.W. and Guelat, J. and Kania, W. and Kery, M. and Koppen, U. and Robinson, R.A. and Schaub, M. and Thorup, K. and Van der Jeugd, H.P. and Van Noordwijk, A.J. (2010) Improving the analysis of movement data from marked individuals through explicit estimation of observer heterogeneity. Journal of Avian Biology, 41, 8-17. ISSN 0908-8857.

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Official URL: http://dx.doi.org/10.1111/j.1600-048X.2009.04907.x

Abstract

Ring re-encounter data, in particular ring recoveries, have made a large contribution to our understanding of bird movements. However, almost every study based on ring re-encounter data has struggled with the bias caused by unequal observer distribution. Re-encounter probabilities are strongly heterogeneous in space and over time. If this heterogeneity can be measured or at least controlled for, the enormous number of ring re-encounter data collected can be used effectively to answer many questions. Here, we review four different approaches to account for heterogeneity in observer distribution in spatial analyses of ring re-encounter data. The first approach is to measure re-encounter probability directly. We suggest that variation in ring re-encounter probability could be estimated by combining data whose re-encounter probabilities are close to one (radio or satellite telemetry) with data whose re-encounter probabilities are low (ring re-encounter data). The second approach is to measure the spatial variation in re-encounter probabilities using environmental covariates. It should be possible to identify powerful predictors for ring re-encounter probabilities. A third approach consists of the comparison of the actual observations with all possible observations using randomization techniques. We encourage combining such randomisations with ring re-encounter models that we discuss as a fourth approach. Ring re-encounter models are based on the comparison of groups with equal re-encounter probabilities. Together these four approaches could improve our understanding of bird movements considerably. We discuss their advantages and limitations and give directions for future research.

Item Type:Article
Institutes:Nederlands Instituut voor Ecologie (NIOO)
ID Code:6437
Deposited On:01 Jul 2010 02:00
Last Modified:24 Apr 2012 16:44

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