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Factors affecting long-term memory of aposematic signals in avian predators
Skoumalová, Žaneta ; Exnerová, Alice (advisor) ; Sedláček, František (referee)
The ability to memorize and recognize edible prey from inedible prey is essential for an individuals survival. Many species use aposematic signals for their defense. These are most often represented by distinctive colors or contrast patterns. The aim of this study was to find out in which time the memory consolidation for aposematic pray is achieved and if color or pattern increase its memorability. The choosen model species was the Great tit (Parus major). The comparision was done between handreared naïve birds and wild-caught adults of different age and sex. During the discriminatory task of consolidation experiment, birds were simultaneously presented with palatable and unpalatable prey in the form of paper dummies of bugs, differing in color (red versus green). The birds were divided into three groups with a different interval (0, 1 or 3 hours) for consolidation. The results of consolidation test show that adult birds were more successfull in solving the task than juvenile birds. The only difference between the experimental groups was that the group with one-hour interval achieved better results than other groups. The effect of color of palatable and unpalatable prey on discrimination learning was also found only in adults. Memorability of warning signals was tested using paper bugs of...
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Factors affecting long-term memory of aposematic signals in avian predators
Skoumalová, Žaneta ; Exnerová, Alice (advisor) ; Sedláček, František (referee)
The ability to memorize and recognize edible prey from inedible prey is essential for an individuals survival. Many species use aposematic signals for their defense. These are most often represented by distinctive colors or contrast patterns. The aim of this study was to find out in which time the memory consolidation for aposematic pray is achieved and if color or pattern increase its memorability. The choosen model species was the Great tit (Parus major). The comparision was done between handreared naïve birds and wild-caught adults of different age and sex. During the discriminatory task of consolidation experiment, birds were simultaneously presented with palatable and unpalatable prey in the form of paper dummies of bugs, differing in color (red versus green). The birds were divided into three groups with a different interval (0, 1 or 3 hours) for consolidation. The results of consolidation test show that adult birds were more successfull in solving the task than juvenile birds. The only difference between the experimental groups was that the group with one-hour interval achieved better results than other groups. The effect of color of palatable and unpalatable prey on discrimination learning was also found only in adults. Memorability of warning signals was tested using paper bugs of...
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Tool use in birds
Skoumalová, Žaneta ; Exnerová, Alice (advisor) ; Nekovářová, Tereza (referee)
Tool use has been observed in many bird taxa, mostly in parrots and songbirds. Tools are primarily used for a purpose of food acquisition and food preparation and physical maintenance. Spontaneous tool manufacture or tool use has been observed in species, which do not use tools in the wild. Tool using is actively performed only by those birds, whose natural environment has a reduced food availability, food is difficult to extract and handle. Tool manufacturing and tool using requires a considerable degree of cognitive abilities, which are experimentally tested in tasks involving use of tools. Differences between species that use tools in the wild, and those that do not are manifested not only in solving experimental tasks, but also in how birds acquire the ability to use tools. While tool users often solve tasks successfully by using causal reasoning, non-tool users are not always capable of solving complex tasks and understanding of the physical properties of the situation. Negative results of these species do not necessarily imply a lack of understanding, but they can also be caused by morphological or environmental constrains, which make tool use more difficult. Tool users also have inherited behavioral patterns, which are further strengthened by individual learning and can be influenced by...
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