SEEN - SE European Bird Migration Network
Orientation statistics 1 - Recovering preferred directions from the single orientation test

Krzysztof Muś
Bird Migration Research Station, University of Gdańsk Przebendowo, 84-210 Choczewo, Poland
k.mus@univ.gda.pl

As the result of the single orientation test in the Busse?s cage we obtain typically eight numbers describing counts of scratches in each of eight 45- degree sectors. These numbers are only information we must transform into directional preferences of the bird. The Bayesian statistical approach in proper model selection was presented. The first step is an estimation of the directional parameters for the assumed number of directions. Models of 0 to 4 directions were investigated for each orientation test. The second step is a selection of the statistically best one from the above models. The Bayesian Information Criterion (BIC) was used for the maximum posterior probability model determination. Directions determined in the single orientation experiments are the starting point in the upper-level modelling of the common directions in the group of birds. Computer program for the orientation modelling is also presented.

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