Population dynamics of grey partridge (Perdix perdix) in northern italy

Abstract

Population dynamics of grey partridge was studied from 1982 to 1986 in northern Italy in order to evaluate fluctuations in density and the relationships between population parameters and climatic factors. The general trend was a clear decrease both in spring and summer density after 1984, weighting 34.6% and 22.2% respec tively, mainly due to severe winters. The reproductive success and the recruitment were negatively correlated with spring density. Brood size significantly decreased through the rearing season and chick mortality occurred mainly within the first 30 days after hatch ing in 1985, while in 1984 it was distributed over the whole growing period. It was also significantly related to the hatching period, earlier broods showing higher mortality. Chick mortality was strongly related to weather conditions in spring, which negatively affected the abundance and distribution of insects. Adult losses from spring to summer were found to be negatively related to reproductive suc cess and positively to spring density. Both density-dependent and climatic factors appeared responsible for a control of population levels. Severe winters and cold springs represented limiting factors: However, the population showed ability to recover by increasing reproductive success and recruitment. © 1991, Taylor & Francis Group, LLC.