Food preferences of grey partridge chicks, Perdix perdix, in relation to size, colour and movement of insect prey.

Abstract

With continually changing arable farming practices, knowledge of the invertebrates in the chick diet of many farmland bird species is important, as it can help in their habitat management and conservation. Although studies have found which groups are represented in the diet, this does not necessarily mean these items are preferred. To gain some understanding of the basic principles underlying a chick's choice of food, we fed grey partridge chicks different insect taxa and coloured food pellets to determine whether preference was related to size, colour or movement of the food items. Trials were conducted against white, brown and green backgrounds. There were significant differences in the overall selection of insect taxa, with wide differences in the probability of selection between items. With no movement, choice was primarily influenced by size and colour. Colour influenced selection for similarly sized items, with a preference for green/yellow over brown/black, but size also affected choice within the most preferred colours. Red was least selected. With live insects, colour and size again had the greatest effect on choice, but movement also affected the selection of smaller items. Selection of uniformly sized coloured food pellets gave a similar colour selection choice to that obtained with insects. However, in natural habitats the preferred larger items, generally green/yellow, could be more difficult to see if immobile and cryptically coloured. They might also be located on vegetation and physically unavailable, restricting choice to the smaller, often active, but less preferred items.