Home-range size of Pyrenean grey partridges Perdix perdix hispaniensis during the breeding season

Abstract

We investigated spacing patterns of Pyrenean grey partridges Perdix perdix hispa niensis during the breeding season (March-September) to refine our recommendations concerning restoration of nesting and brood rearing habitats. The study was based on 30 grey partridges, 24 yearlings (9 males, five females) and six adults (five males, one female) radio-monitored in two study areas of the eastern Pyrenees. Movements and home ranges were analysed for the pre-and posthatching periods. For each bird and period, we used cluster analysis to identify core areas within home ranges. Throughout the breeding season, 24 of the 30 birds were paired and six yearling males remained unpaired. The latter used larger home ranges than paired birds, at least before hatching. The home-range size (Minimum Convex Polygon) of the 24 pairs averaged 8 ha in spring (from pair formation to hatching) and 26 ha in summer (brood-rearing period). Pairs tended to use larger core areas after hatching (mean = 0.8 ha) than before (mean = 6.2 ha). After hatching, broodless pairs used larger core areas (mean = 4.4 ha) than those with broods (mean = 8.7 ha). For both groups, we found little overlap between core areas used before and after hatching. For unsuccessful breeders, the small overlap was associated with post-breeding movements to higher altitudes. For successful breeders, it was related to movements to brood rearing habitat. Daily inter-fix distances of broods averaged 26 m during the first three weeks after hatching, then regularly increased up to 249 m as chicks exceeded the age of six weeks. The size of core areas used by broods indicates that treatment plots should cover 5-0 ha to restore breeding habitats with a diversity of shrubland vegetation types.

Decline and potential recovery of the European grey partridge (Perdix perdix) population—a review

“…The lesson can be learned that instead of using linear elements it is better to create blocks of improved habitat, which are big enough to avoid an ecological trap. Sotherton (1998) mentions a minimal size of each block of 0.3 ha with a width of 20 m. Besides, grey partridges are territorial during the breeding season and each pair uses and area of 6-10 ha (Buner et al 2005;Novoa et al 2006) or smaller than 2 ha in areas with good habitat (Šálek et al 2004). The creation of only a few blocks will then be beneficial for only a few individuals.…”

Spatial movements of grey partridge Perdix perdix: male-biased spring dispersal and effect of habitat quality

“…Considering a span within home ranges of 100-800 m during breeding and 300-600 m during summer, plus the autumn movements that have been found in Prague (Š álek et al 2002b), the dispersal distances resembled routine movements within home ranges rather than displacements limiting straightforward returns (Van Dyck and Baguette 2005). Therefore, habitat conditions in Central Europe that adjust the carrying capacity for the Grey Partridge to about 2-5 pairs per 1 km 2 , as found in our study area (Šálek and Marhoul 1999) and recently also in Poland (Panek 2005), do not seem to be below the threshold initiating strong dispersal behaviour, as observed at the edge of the northern distribution range of the species in Finland (Putaala and Hissa 1998), in extreme Pyrenean habitats (Novoa et al 2006), or in some introduced populations in North America (Carroll 1990;Church and Porter 1990). Although we cannot rule out that some of our radiotagged partridges undertook long-distance dispersal, their omission should not bias our basic findings.…”

“…A surplus of males has been found as a rule in spring Grey Partridge populations (Blank and Ash 1956;Potts 1980;Weigand 1980;Aufradet and Birkan 2001;O'Gorman and Kavanagh 2002;Šálek et al 2002a;Novoa et al 2006). This is thought to result from high female mortality during the previous breeding season (Potts 1980).…”

“…Adults should pair off first, so that most single cocks are juveniles who leave the coveys to search for mates elsewhere (Jenkins 1961;Aufradet and Birkan 2001). However, some pairs also perform spring dispersal regardless of population density and the amount of nesting cover (Potts 1986;Birkan and Serre 1988;Novoa et al 2006). The pre-breeding dispersal patterns of Grey Partridges thus seem be very variable from site to site, probably reflecting the availability of suitable habitats, population density, age structure and origin of individuals (wild or introduced).…”

“…This is thought to result from high female mortality during the previous breeding season (Potts 1980). Unpaired males tended to be nomadic in spring (Blank and Ash 1956;O'Gorman and Kavanagh 2002;Novoa et al 2006), though many of them behave like sedentary birds (Aufradet and Birkan 2001). Adults should pair off first, so that most single cocks are juveniles who leave the coveys to search for mates elsewhere (Jenkins 1961;Aufradet and Birkan 2001).…”