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

Abstract

The Grey Partridge Perdix perdix is a sedentary species with a surplus of males in spring populations. It experienced a dramatic decline in Europe primarily due to habitat loss that may have forced the species to modify its dispersal behaviour, a less transparent source of populations threats. We analysed the dispersal patterns of Grey Partridges during pre-and post-breeding periods in two landscapes with different habitat quality in the Czech Republic. Grey Partridges tended to pair off quickly, with most pre-breeding movements executed in pairs. The birds usually dispersed over a few hundred metres indicating that the habitat conditions in a landscape with a carrying capacity of 2-5 pairs/1 km 2 was not below the threshold initiating strong dispersal, as observed in extreme habitats and at the northern limits of the specieś distribution range. A few single males that had remained unpaired until April also finally bred. However, the high level of sedentariness of males in a good landscape suggested that males prefer to stay near wintering sites unless habitat sources become limited. Unlike the males, the females dispersed in a wide range of distances with an extensive overlap in both landscapes. Autumn movements did not differ between the sexes, but were longer than the pre-breeding movements and increased in a poor landscape. We conclude that both reduced habitat availability and reduced mating opportunities initialise primarily male-biased breeding dispersal in Grey Partridge populations.

Sex‐ and age‐biased mortality in wildGreyPartridgePerdix perdixpopulations

“…However, searching for a partner is linked to more extensive movements, at least up to the hatching period (Novoa et al . , Šálek & Marhoul , own observations), and unpaired individuals suffer higher mortality than those paired (Potts , , Carroll ), especially due to raptor predation (Potts ).…”

Habitat preferences and similarities of Grey Partridges and Common Pheasants in agricultural landscapes under organic and conventional farming

“…With a value ranging from 0 to 1, B i gives the estimated probability that a habitat type would be the next one selected, if all habitat types were equally available. We assume that habitat types within the 29 squares were available for all animals within the study site because average distance between squares dominated by conventional and organic farming (mean ± SD, 2266 ± 847 m) was similar to dispersal distances found for Grey Partridges (see Šálek and Marhoul 2008;Rymešová et al 2013) and Common Pheasants (Felley 1996). Therefore, analyses were made at the population level (Manly design I).…”