BRANTA — Roger A.H. Draycott
Effects of supplementary feeding on the body condition and breeding success of released pheasants
Institution: University of Oulu, Finland
Supervisors: A Putaala
Details: PhD 2002 (Completed)
Address: The Game Conservancy Trust, Fordingbridge, Hampshire, SP6 1EF (Oct 2005) Email
Subject Keywords: Captive-rearing, diet, food availability, grain, survival
Species Keywords: Common Pheasant Phasianus colchicus
Abstract
The breeding success of released pheasants (Phasianus colchicus) is poor compared with wild ones in Great Britain. Many factors have been cited as possible causes of poor breeding success, including reduced hen condition in the nesting season. The aims of this study were to determine whether reduced body condition due to an inadequate diet contributes to poor breeding success of released pheasants and to demonstrate experimentally the impact of supplementary feeding on their body condition and breeding success. A series of 6 studies of food availability, diet, body condition and breeding success of pheasants was conducted in Britain between 1994 and 2000 to study these questions.
Spring diet and food availability were assessed in a multi-site study. Grains and seeds are important dietary components, but their availability to pheasants and their occurrence in the diet was low on all sites during spring. Grains were only a significant component in the diet on sites where supplementary feeding continued into spring. A spring survey of hen pheasant body condition on 21 sites revealed that fat reserves were higher on sites with spring supplementary feeding compared with sites which ceased feeding at the end of the shooting season (1st February). Further, it was demonstrated experimentally that continuing feeding into spring enabled hens to maintain fat reserves at their winter levels, whereas fat reserves of hens in unsupplemented areas were reduced by up to 50%. Supplementary feeding did not improve survival of hens through the spring, but the pre-breeding density of territorial cocks and hens was increased. Feeding did not significantly influence measured productivity parameters except for aspects of re-nesting ability which were improved by feeding. Overall, the density of young birds observed during autumn counts were twice as high in plots which had been provided with supplementary grain in the previous spring than in unfed plots.
Although population densities of pheasants were positively influenced by supplementary feeding, breeding success was still lower than that of wild birds. Clearly, there are behavioural and physiological deficiencies which pre-dispose released pheasants to poor performance in the wild. Habitat deficiencies other than adult food availability are likely to be important too; in particular, the quality of brood rearing habitat which influences chick survival. However, the results of this study contribute to our knowledge of the ecology and management of released pheasants and it is recommended that spring feeding should be conducted routinely by game managers to enable released hens to maintain body condition and maximise their breeding potential.
Published Papers
Draycott, R.A.H., Butler, D.A., Nossaman, J.J. & Carroll J.P. 1997. Availability of weed seeds and waste cereals to birds on arable fields in spring. In: 1997 Brighton Crop Protection Conference - Weeds. BCPC, Farnham. 1155-1160.
Draycott, R.A.H., Butler, D.A. & Carroll J.P. 2000. Spring diet of pheasants in the UK: Implications for the body condition of nesting hens. Hungarian Small Game Bulletin 5:29-37.
Draycott, R.A.H., Hoodless, A.N., Ludiman, M.N. & Robertson, P.A. 1998. Effects of spring feeding on body condition of captive-reared ring-necked pheasants in Great Britain. Journal of Wildlife Management 62: 557-563.
Hoodless, A.N., Draycott, R.A.H., Ludiman, M.N. & Robertson, P.A. 1999. Effects of supplementary feeding on territoriality, breeding success and survival of pheasants. Journal of Applied Ecology 36: 147-156.
Draycott, R.A.H., Parish, D.M.B., Woodburn, M.I.A. & Carroll, J.P. 2002. Spring body condition of hen pheasants in Great Britain. Wildlife Biology 8: 261-266.
Draycott, R.A.H., Woodburn, M.I.A., Carroll, J.P. & Sage, R.B. 2005. Effects of spring supplementary feeding on population density and breeding success of released pheasants Phasianus colchicus in Britain. Wildlife Biology11: 177-182.