The food composition of Grey Partridge chicks Perdix perdix in central Finland

Abstrakti

The purpose of this study was to investigate the composition of the diet and food selection of grey partridge chicks Perdix perdix in northern ranges . The study was carried out in the municipality of Tyrnävä, in central Finland (64'47'N, 25'40'E), in the middle of ca. 20 km2 of arable land. Three grey partridge broods were followed with the aid of radio transmitters placed on the back of females. The night roosting places were located and droppings of the chicks were collected. Four droppings from every second night were analysed to investigate the diet of the chicks during their first weeks. Reference material was collected by pitfall traps and by sweep net. Chicks used a diverse assortment of invertebrates, but cicadas and beetles were most numerously eaten. When the abundance of different invertebrate taxa was taken into account, chicks preferred Delphacidae, Carabidae, larvae of Silphidae, Chrysomelidae, other Coleopteras and Aphidoidea, whereas they consumed less invertebrates than expected belonging to taxa of Diptera and Araneae. Despite the uniform selection of certain insects, the variation of food composition between broods was large. In a DCAordination the droppings of different broods are presented as their own subgroups, with only a few droppings overlapping. During the first three weeks the diet of the chicks was primarily composed of invertebrates . The proportion of plant material increased slightly towards the end of the study period .