The grey partridge became extinct in the province of Siena (central Italy) in the late seventies, whereas the red-legged partridge had already disappeared by the beginning of the twentieth century. Some reintroduction attempts of both species carried out in the 1980s gave encouraging but not definitive results, and failed after an initial success. This was probably due to the low number of birds released, the small size of the re-introduction areas, their isolation, the farm-bred origin of the partridges, and hunting. In the province of Siena, for the first time in Italy, a large-scale reintroduction program of grey and red-legged partridges was experimented. The project started up in 1995 with seven reintroduction areas for grey and four for red-legged partridge, and was extended to 19 areas (22,562 ha) for grey and 7 (6858 ha) for red-legged partridge in 2002. Population viability analyses for both species showed that if reintroduced populations were isolated they would be extinct in a few years. Therefore, a metapopulation approach was adopted (contemporary releases in reintroduction areas close to each other). In each area, 100-1000 partridges per year were released for a minimum of 3 years, from different farms in order to achieve the maximum initial genetic diversity. Releases were effected in late summer (August-September) in acclimatization pens containing 10-20 aviaries. The reintroduced population showed marked variability of some demographic parameters, such as pair density and brood production rate; instead, average brood size was relatively constant across the study areas, but with annual variations. Reintroduction success was limited to a few areas only, mainly depending on the habitat characteristics of the areas, their surface area and isolation, and on the degree of care for the birds during the acclimatization period.
In female mammals, reproduction requires high-energy expenditure because of gestation and lactation; therefore, a fitness cost of current reproduction may lead to a decrease in future survival or reproduction. The reproductive cost differs between short-lived species with a fast life history strategy compared to long-lived species with a slow life history strategy. We used harvest data on reproduction and body mass from two small-sized and short-lived mammals, mountain and European hare (Lepus timidus and Lepus europaeus) to explore the cost of reproduction and determine how the number of newborns produced in the current breeding season affects female body mass at the end of the reproductive season. Within a reproductive season, female hares experienced a reproductive cost: current litter size was negatively affected by the number of newborns produced in the current breeding season until the current litter. In the given reproductive season, females that had had more litters also had the highest reproductive output and had higher body mass at the end of the breeding season. The presence of a reproductive cost and the high reproductive performance of heavier female hares suggest a strategy of reproduction more conservative than expected for a species with a relatively small size and fast life history strategy. Heavier female hares seemed to be able to face the cost of reproduction, produce more offspring and remain larger at the end of the reproductive season: a strategy that is more conservative than risky. We believe female hares adopt, at least in part, a conservative strategy of reproduction characterized by an increased number of litters per season because of the positive fitness payoff gained.
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