Introduction
When undertaking any reintroduction program, it is important to consider the geographic origin between released individuals and the original population. Introgressive hybridization between nonlocal translocated organisms and local wild populations can have unforeseen genetic effects on the indigenous population since it potentially affects local adaptation in the native wild population when pairing between translocated and native individuals takes place (Randi, 2008).
Although the grey partridge (Perdix perdix) is considered to be common and not threatened on a global scale, its populations appear to be declining in intensively farmed areas most likely due to a reduction in breeding sites and food stocks (Ewald, Sotherton and Aebischer, 2020). In Europe, since the beginning of the 20th century, there has been a drastic decline in grey partridge populations in all of the 31 countries it is found (Kuijper, Oosterveld and Wymenga, 2009). For example, its breeding abundance fell by 92% from 1967 to 2022 across the UK probably due to the intensification of agriculture (BirdTrends 2023, www.bto.org/birdtrends). For this reason, the grey partridge has been Red-listed as a Bird of Conservation Concern and the British government launched a major programme to help partridge recovery in the UK nearly 20 years ago (Aebischer and Ewald, 2012). Population shrinkage is also observed in southern populations of grey partridge like Greece where, mainly from 1950 and onwards, there has been a drastic population decline (Thomaides, C. & Papageorgiou, 1992). For this reason, the hunting of grey partridge has been prohibited in Greece since 1984. Releases in Greece have also taken place with farmed individuals imported mainly from countries in the Balkans and Northern Europe of unknown provenance. Several studies have clearly shown that the survival of hand-reared birds is poor after their release into the wild (Liukkonen, 2006). It has been suggested that differences in the genetic adaptation of separate subspecies (P. p. lucida , P. p. perdix ) to different climatic conditions of their original range could be a partial explanation for the failed introductions (Liukkonen, 2006). Therefore, it is of utmost importance that a genetic analysis of wild populations is carried out.
Genetic provenance of individuals is a key assessment criterion in the IUCN guidelines for reintroductions and translocations (IUCN 2013) as both inbreeding and outbreeding depression are potential concerns. Some genetic information is available for European populations of grey partridge; phylogeographical analysis of 227 birds from several localities based on mitochondrial DNA sequencing revealed a distinction of populations in two major clades (western and eastern) in agreement with the subspecies taxonomy (Liukkonen, 2006). However, little is known about the genetics of range-edge populations, such as those in Scotland and the Southern Balkans, Greece and North Macedonia. No individuals have been sampled so far from Scotland while a genetic study with less than 10 individuals from Greece revealed that the Greek population belongs to the eastern group (Liukkonen-Anttila et al. , 2002; Liukkonen, Kvist and Mykrä, 2012).
We use genetic analyses to study a Northern and a Southern wild and farmed European population of grey partridge, comparing the provenance of each. Our results will complement efforts to manage and support wild native populations by providing important insights into the status of these populations, namely on the levels of genetic diversity and the impact of past restocking activities. This could have implications for the sourcing of released birds as breeding between released stocked and wild partridges may complicate the recovery of partridge populations.