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Interspecies differences in the cognitive abilities of corvids
Myslivečková, Lucie ; Fuchs, Roman (advisor) ; Sedláček, František (referee)
Birds from the family Corvidae are considered to be intelligent birds. Many species from this family are subjects of experiments that study their cognitive abilities. This thesis was focused on gathering and evaluating of comparative studies about interspecies differences in the cognitive abilities of two or more species. A part of the thesis was also dedicated to interspecies differences in cognitive abilities in corvids and other animal species. Result is that there are interspecies differences in cognitive abilities of corvids. These differences are cause mostly by their feeding ekology and the sociality of the specie. The success rate of different species can change depending on the experiment. Key words: Corvidae, corvids, cognitive abilities, interspecific comparison, comparative approach
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Ravens respond to unfamiliar corvid alarm calls
DAVÍDKOVÁ, Marika
The following work encompasses a research in the behaviour of the common raven (Corvus corax). I tested the responses of the common raven to heterospecific alarm calls of various bird species that differ in familiarity and taxonomical relatedness to ravens. Two other corvid species (jays) and two non-corvids (gulls) were presented. The ravens were given stimuli from one jay and one gull - one of which was always familiar to the tested ravens (European) and one unfamiliar (American). The results suggest that familiarity is not as important as the membership to the Corvidae family.
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Antipredation behaviour of the Red-Backed Shrike (\kur{Lanius collurio}) against corvids
NĚMEC, Michal
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
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