1. Department of Ecology and Vertebrate Zoology, University of Łódź, Łódź, Poland; e-mail: grzegorz.zieba@biol.uni.lodz.pl, miroslaw.przybylski@biol.uni.lodz.pl
2. School of Animal, Rural and Environmental Sciences, Nottingham Trent University, NG25 0QF, UK; e-mail: carl.smith02@ntu.ac.uk, rowena.spence@ntu.ac.uk