Demographic parameters of reintroduced grey partridges in central Italy and the effect of weather

International audienceGrey partridge populations declined in Europe from mid-1950s onwards mostly due to modifications of agricultural cropping. In Italy, the decline was even more dramatic because of over-hunting and restocking with allochthonous birds. We carried out a research on a re-introduced population in Central Italy from 1995 to 2005, with the aim of evaluating the reintroduction success and separating the intrinsic and external factors influencing year-to-year changes in partridge density with particular respect to the weather. Average spring density was 4.5 pairs per square kilometre (SD = 1.52); our population reached a peak few years after the reintroduction and then declined. Brood production rate was close to that of declining European populations (average 33.9%; SD = 10.21), and chick survival rate (average 40%; = 17.61) determined the change of breeding abundance from year to year + 1. Our population seemed to be mainly affected by brood production and chick survival rates and by the weather; in particular, higher early winter and spring temperatures increased breeding density whilst higher early summer temperatures decreased brood production rate

Changes in habitat selection patterns of the gray partridge Perdix perdix in relation to agricultural landscape dynamics over the past two decades

International audience1. Changes in agricultural practices have reshaped agricultural landscapes and triggereda drastic decline in spatial and temporal heterogeneity leading to changes inhabitat quality and food resources for birds. However, the precise relationshipsbetween landscape changes, spatial and temporal heterogeneity, and habitat preferencesin response to those changes remain poorly known.2. We investigated patterns of habitat selection and causes for changes over theyears 1997–2017 for the gray partridge Perdix perdix, an iconic farmland specieswhich has experienced a severe decline since the 1950s. Using a long‐term (1997–2017) dataset collected over 435 km2, we modeled relationships between annualland‐cover maps and partridge sightings over 17 5‐year moving windows, assessingthe effects of landscape metrics, the strength of the relationships, and thedynamics of habitat suitability.3. We detected a shift in gray partridge habitat preferences over time, toward morerisky habitats. Avoidance of predator reservoirs (woodlands and buildings) hasweakened, and selection of human infrastructure, such as roads and tracks, hasincreased. Since 1997, the mean size of suitable patches has also decreased byabout 26%.4. We have interpreted these changes in habitat selection as being the result of decreasinghabitat quality and the increasing prevalence of captive‐reared birds, currentlyreleased in their thousands in the study site.5. Synthesis and applications. The gray partridge has not adjusted well to changes infarming practices, and the low, still decreasing, population density suggests that itis not sustainable, despite local initiatives and the investment in captive‐bird releases.We emphasize that efforts must be redirected toward habitat improvementto restore the density of refuge cover, insects, and seeds in the landscape,hunting management to ensure self‐sustainable populations and massive releasesof high‐quality birds. Only integrated local management, involving hunters, farmers,gamekeepers, and scientists can ensure the recovery of this species