Birds as predators
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 leads to predator’s association of noxiousness with the colour pattern which later results in avoiding the aposematic form of the prey in the future. Avoiding aposematic prey could be innate or learned through the life. This kind of protection is present in many animal species. Our aim is studying predator responses to such aposematic prey.
Our experimental apparatus is a special cage. Its front wall is an one-side transparent mirror used in order not to disturb behaviour of the observed bird with the presence of an experimentator. Experimental prey is presented to the bird on a revolving feeder tray and bird behaviour is recorded by the Observer programme for 5 minutes per one item of prey. This programme is usually used for collecting ethological data. Depending on the type of research, each bird is usually offered 10 items of prey (one for each trial) – alternating one mealworm and one bug/cockroach/cricket, it means 5 mealworms and 5 bugs/cockroaches/crickets of the same colour form totally. Mealworms are presented to prove that the bird is motivated to feed, and therefore to be sure that avoiding experimental prey is due to its aposematic signal. Trial repetition can reveal 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.
People involved in this research: