This thesis summarizes findings on a recognition and categorization of different sorts of stimuli at birds, it deals with predator recognition in the Red-backed Shrike (Lanius collurio) in its practical part. The aim of my study was to examine if Red-backed Shrikes follow by sign stimuli or colour of stimulus during the predator recognition. I performed my research by means of experiments with dummies, I have observed antipredatory reactions of Red-backed Shrikes on various types of dummies which differ in the presence or absence of features of raptor or in the different coloration. I concluded according to Shrikes' reactions that during the predator recognition the information on sign stimuli playes the principal role, but only this information alone is not fully sufficient. Antipredatory behaviour of the Red-backed Shrike was also influenced by sex of bird apart from type of dummy, males were more active during the nest defence than females.

In previous studies with stuffed dummies, we found interesting difference in nest defence of Red-Backed Shrike (Lanius collurio) against two similar nest predators: Jay (Garrulus glandarius) and Magpie (Pica pica). Jay was attacked very intensively, whereas Magpie almost wasn´t hited and Shrikes seemed to keep in cover. Here, I describe the antipredation behavior of the Red Backed Shrike against another stuffed corvids presented closely to Shrikes nests: Jay (Garrulus glandarius), Common Nutcracker (Nucifraga caryocatactes), Rook (Corvus frugilegus), Crow (Corvus corone) and Raven (Corvus corax). I found Jay and Nutcracker to be attacked by Shrikes very strongly, whereas Rook, Crow and Raven were attacked rarely (Shrikes only flied around them or sit at a distance, watching the dummy, sometimes accompanied with alarm-calls). Shrikes response is affected mainly by kind of predator, by age of youngs and by quality of concealment of nest. More - www.mn.ic.cz