Effects of spring supplementary feeding on population density and breeding success of released pheasants Phasianus colchicus in Britain

The release of hand-reared ring-necked pheasants Phasianus colchicus in summer is a common practice in Britain to increase the number of birds available to hunters in winter. The breeding success of the birds which survive the shooting season is poor. Traditionally, birds are provided with supplementary wheat grain from release until the end of the shooting season (I February) to maintain body condition and to help hold birds in areas for hunting. During 19972000 we assessed the effect of continuing supplementary feeding into spring on pheasant density and breeding success on seven private shooting estates. On each estate we randomly selected two distinct 1-km(2) plots and provided wheat grain via feed hoppers for birds in breeding territories in one of the plots on each estate while the other plot acted as an untreated control. Food was provided from mid-February to mid-May. We crossed-over the treatment and control plot on each estate each year. We conducted pre- and post-breeding pheasant counts in the plots during April and September. During April, densities were higher in treatment plots than in control plots for territorial males: (mean SE) treatment = 22.6 +/- 1.5 birds/km(2), control = 14.8 +/- 1.2 birds/km(2), (P < 0.001) and for females: treatment = 40.6 +/- 5.8 birds/km(2), control = 24.1 +/- 3.8 birds/km(2) (P < 0.001). In September we found no statistical effect of treatment on densities of adult birds or on brood size. However, more young were observed on treatment plots: 10.8 +/- 1.5 birds/km(2), than in control plots: 5.6 +/- 1.0 birds/km(2), (P = 0.02). In order to improve the breeding potential of released pheasants, we recommend that spring supplementary feeding is undertaken on shooting estates in Britain.