The prey recognition in birds, aposematism

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CCE - Center of Cognitive Ethology / CKE - Centrum kognitivní etologie
Faculty of Science, University of South Bohemia, Branišovská 31, 370 05, České Budějovice, Czech Republic (map).


Aposematism is a special part of communication between predator and its prey. It combines conspicuous coloration with noxiousness (in many cases with unpalatability). Function of aposematism is to protect the prey against predator. Aposematism results in predator`s association of noxiousness with the colour pattern and therefore next avoiding the aposematic form of the prey in the future. Avoiding aposematic prey could be innate or learned through the life. This kind of protectivity is present in many species of animals. Studying of the response of the predator to such an aposematic prey is the aim of my master thesis.

The experimental apparatus is a special cage. Its front wall is made of one-side transparent mirror in order not to disturbe behaviour of the processed bird by the presence of experimentator. Experimental prey is presented to the bird on a revolving feeder tray and behaviour of the bird is noted by programme Observer, ver. 5.0, for 5 minutes per one item of prey. This programme is usually used for collecting ethological data. Each bird is offered 10 items of prey (one for each trial) – alternating one maggot and one bug, it means 5 maggots and 5 bugs of the same colour form totally. Maggots are presented to prove that the bird is starving and to be sure that avoiding experimental prey is due to its aposematism. Repeating of the trial can reveal us individual learning of the bird through the whole experiment.

Through the experiment, different types of predator’s behaviour are distinguished - exploring, searching, approaching, handling prey, feeding prey, vomiting, resting, drinking and cleaning the bill. Presence, frequency and total duration of different types of behaviour is noted in each trial. Species of bird, its age and sex, period of year, colour of bug and order of trial in frame of the experiment will be explanatory variables in the statistical analysis. Nowadays I’m at the end of the first part of my thesis (collecting enough data). The second part (statistical analysis) is still to come.

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