Studies on the changing role of weeds of the genus Polygonum in the diet of the partridge Perdix perdix L.

Abstract

Surprisingly little is known of the food of adult partridges in Britain at the present time and there has been no investigation of the relative availability of the food species which are known to be eaten. On the other hand, several analyses, particularly those of Middleton & Chitty (1937), Janda (1957) and Pulliainen (1965, 1968) have shown that about one-third of the dry weight of the food from late summer to spring consists of weed seeds. The remainder of the food is mainly grain and, especially in winter and spring, green leaves.

This paper investigates the weed seed diet of the grey partridge (Perdix perdix L.) in relation to the changes in the weed flora which have resulted from improved agriculture. The seeds and leaves of cultivated and wild Graminae and cereal weeds such as Alopecurus myosuroides, Agropyron repens, Avena fatua and A. ludoviciana, are likely to remain abundant into the foreseeable future, so they have not been considered in the present study. In marked contrast, the status of dicotyledonous weeds as a whole is uncertain; many species are decreasing and others have become very scarce.

Special attention is given to the species of Polygonum since they are usually the most important dicotyledonous weeds in the diet of the grey partridge. The recent introduction of 3,6-dichloro-2-methoxybenzoic acid (dicamba) and 2-(2, 4-dichlorophenoxy) propionic acid (dichlorprop) for the control of Polygonum spp. largely prompted this study.