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

TY - JOUR

T1 - Improving the analysis of movement data from marked individuals through explicit estimation of observer heterogeneity

AU - Korner-Nievergelt, F.

AU - Sauter, A.

AU - Atkinson, P.W.

AU - Guelat, J.

AU - Kania, W.

AU - Kery, M.

AU - Koppen, U.

AU - Robinson, R.A.

AU - Schaub, M.

AU - Thorup, K.

AU - Van der Jeugd, H.P.

AU - Van Noordwijk, A.J.

N1 - Reporting year: 2010 Metis note: 4741;CTE; VT; file://L:\EndnoteDatabases\NIOOPUB\pdfs\PDFS2010\Korner-Nievergelt_ea_4741.pdf

PY - 2010

Y1 - 2010

N2 - 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.

AB - 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.

U2 - 10.1111/j.1600-048X.2009.04907.x

DO - 10.1111/j.1600-048X.2009.04907.x

M3 - Article

SN - 0908-8857

VL - 41

SP - 8

EP - 17

JO - Journal of Avian Biology

JF - Journal of Avian Biology

IS - 1

ER -