Re-evaluation of the role of the grey partridge Perdix perdix as a disperser of arable weed seeds

Abstract

The endozoochorous dispersal of weed seeds, mediated by birds and without any adaptation to frugivory, has been studied very rarely. We studied the endozoochorous dispersal of viable seeds by the grey partridge Perdix perdix in agricultural landscape. We assessed the content of intact seeds in 609 grey partridge droppings coming from 21 sampling sites in Poland that included three land-cover types (winter cereals, winter oil-seed rape and stubble fields). We found 159 intact seeds of 13 plant species. Most of them are classified as plants without any evolved adaptations to dispersal. The number of intact seeds retrieved from droppings was positively correlated with the proportion of seeds and negatively correlated with total proportion of leaves in the diet. This result may indicate that the consumption of large numbers of seeds increases the possibility that some of them will resist digestion and be excreted with faeces. Our results showed that the highest number of intact seeds recovered from the droppings coming from stubble fields was the consequence of the importance of weed seeds in the diet of grey partridge in this type of land-cover. The grey partridge is a poor seed disperser and rather, it plays an important role as a predator of weed seeds.