The feeding ecology and survival of partridge chicks (Alectoris rufa and Perdix perdix) on arable farmland in East Anglia.
Broods of grey and red-legged partridges were radio-tracked for 20 days after hatching and their diet estimated from faeces collected at nocturnal roosts. Grey partridge chicks foraged in cereal fields and red-legged partridge chicks in cereal, carrot and sugarbeet fields. Chicks of both species fed on arthropods, weed seeds, leaves, flowers and cereal grain but grey partridge chicks were more insectivorous than red-legged partridges. Both species preferred to feed at the edges of fields, where arthropods and weeds were more abundant, and among cereals they preferred winter wheat fields which had the highest densities of arthropods and grass seeds. Periods of brood activity and resting were monitored by continuous recording of radio signal strength. Activity was reduced during periods of low temperature and rain or dew. Surveys of chick survival rates and food supplied on different farms showed that the survival of grey partridge chicks increased with increasing density of prey arthropods. Red-legged partridge chick survival was influenced by the abundance of arthropod prey and grass seeds. Mean survival rates for partridge chicks estimated annually for samples of farms in East Anglia showed that survival increased with June and July temperature for both species. It is uncertain to what extent weather affects chick survival directly via its effect on chick activity rather than indirectly via effects on food supplies.