1 Department of Animal Production (Wildlife Division), Faculty of Life Sciences and Engineering, University of Lleida, 25198 Lleida, Spain; Division of Conservation Biology, Institute of Ecology and Evolution, University of Bern, CH-3012 Bern, Switzerland; and amargalida@prodan.udl.cat.
2 Department of Mathematics, Faculty of Life Sciences and Engineering, University of Lleida, 25198 Lleida, Spain.