Examining the spatial relationship between pheasant (Phasianus colchicus) release pens and grey partridge (Perdix perdix) population parameters

Abstract

As UK grey partridge (Perdix perdix) numbers declined over the last half century, shooting estates changed the emphasis of game management, from wild grey partridges to reared released pheasants (Phasianus colchicus). A recent theory suggested that parasites carried by reared released pheasants may be partially responsible for the decline in the numbers of grey partridges. We used long-running monitoring data from two sites in lowland England to look for relationships between proximity to pheasant release pens and grey partridge population parameters 1. At one study area, 20 km2 for 18 years proximity to release pens was associated with young-to-old ratio. However, the effect of proximity to release pens was probably an effect of habitat composition, as partridge-friendly habitats such as beetle banks and cereal crops were found away from release pens, with less favoured habitats such as grass, winter game cover crops and natural regeneration set-aside being found near release pens. 2. In the other study area, 62km2 for 33 years we found no effect of proximity to release pens on grey partridge density, fecundity or survival.