The effect of aposematism and food calls on the feeding behaviour of domestic chicks

Aposematism is a defence system used by toxic animals where the animals use warning colouration, often combined with warning gestures, to fend off predators. The most probable scenario is that the toxicity was developed prior to the warning colouration. Compared to other survival strategies, aposematism do not rely on the preys capability to hide, run away from or fight off the predator, but rather to be seen and avoided. Chicks will be influenced by the colour of the food, and how it tastes, to assess if the food is interesting and eatable or not. The hen will use sound to attract chicks to the food source, but will this overrule the aposematic colouration of prey? My hypothesis is that the chicks will eat most brown prey, with eating fewer bad tasting, and even fewer aposematic bad tasting. Further on my hypothesis is that the chicks that will be given sound during eating will eat more prey, compared to chickens not given sound during eating. In the experiment 96 domestic chicks, divided into 8 groups (sound or no sound, and bad tasting or neutral prey) were used. The chicks were trained and then tested in 4 days. In the first 12 trials (learning) green and yellow prey tasted bad, and brown tasted good. Green was bad tasting neutral, yellow bad tasting aposematic. In the last 3 trials (extinction learning) green, yellow and brown tasted good. Yellow prey is eaten more often than green prey during the learning tests, but chicks given yellow prey also show a higher amount of learning form day 1 to day 3, compared to chicks given green prey, although not always confirmed statistically. Sound did have an impact on the chicks attack rate, but it did not follow a clear pattern, and it too also shows no significant difference between different sound groups. In the extinction tests, chicks given green prey shows a higher degree of extinction learning, even though not statistically confirmed, as too with sound.