FLUCTUATIONS IN A PARTRIDGE POPULATION 



T. H. Blank and J. S. Ash 



Game Research Station, Fordiiigbridge 



The data presented in this paper have been collected from a 3,600 acre 

 (1,454 hectare) area in West Hampshire. A brief description of the area and 

 methods used in data collecting have been given elsewhere (Blank & Ash, 

 1955). Censuses have been carried out in March, September and December; 

 while a sample count of from one-third to one-half of the March population 

 has been made in August. In addition, more than half of the partridge nests 

 have been found each year, and this nesting data, together with the informa- 

 tion obtained from the examination of birds shot in October, provides the 

 basis of the material concerning a partridge population. It should be pointed 

 out that this partridge population is a mixed one consisting mainly of the 

 Partridge {Perdix perdix), but also containing a small proportion of Red- 

 legged Partridges {Alectoris rufa). The latter average approximately 5 per 

 cent of the breeding population, but have varied from 2- 8 per cent to y 6 per 

 cent. Data concerning the two species have been obtained separately, except 

 for the September and December censuses (when the method of counting 

 makes it difficult to distinguish between the two species), but since the 

 differences between the species and the proportion of Red-legged Partridges 

 are both small, the data for the two species has been pooled (unless otherwise 

 stated). The exploitation of this population has consisted mainly of controlled 

 shooting in the auturon so that an adequate breeding stock will be present 

 the following spring, together with a system of nest protection intended to 

 ensure a relatively high nesting success. By these means an auturmi surplus 

 which can be shot has been created. Habitat improvement, supplementary 

 feeding and the release of hand-reared partridges have been attempted on 

 such a small scale that it is unhkely that they have had any appreciable effect 

 on the population figures. 



Autumn populations have shown well-marked fluctuations over the 

 eleven-year period, with peaks in 1949, 1952 and 1957 and lows in 1954 and 

 1959. If the autumn population is compared (Fig. i) with the breeding density 

 of the previous spring, it will be seen that high autumn populations have 

 resulted from both low (1949) and high (1952, 195?) breeding densities. Low 



