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European wild rabbits Oryctolagus cuniculus are native to the Iberian Peninsula in southwestern Europe ([Monnerot et al., 1994]). Their range has expanded naturally to most of continental Europe, and humans have introduced them worldwide for food or hunting ( [Monnerot et al., 1994]). In most countries where rabbits are found they are considered pests, and hunting is an environmental and economic necessity to control rabbit populations to avoid crop damage and/or the extinction of native species ( [Sheail, 1991, Drollette, 1996, Hone, 1999 and Angulo, 2001]).

In the Iberian Peninsula, however, rabbits are regarded as the staple prey of the Mediterranean ecosystem ([Valverde, 1967]). They sustain a large number of predator species and generate economically important hunting activity, with over 30,000 private hunting areas covering more than 70% of the region ( [Villafuerte et al., 1998]). The progressive decline in wild rabbit populations on the Iberian Peninsula is a concern ( [Beltrán, 1991]), and current numbers are the lowest in decades ( [Villafuerte et al., 1997]).

Effective management of hunting resources requires knowledge of the current regulations and the effects of regulations on the sustainability of wild populations. In Spain (Iberian Peninsula), hunting regulations mainly take the form of hunting quotas set by individual hunting associations and the open hunting season set by the Spanish Government (mainly from October to December). In both cases, regulations are not supported by scientific studies and measures are implemented without knowledge regarding their effects on wild rabbit populations.

Hunters are distributed throughout the Spanish territory, and meet in specific hunting areas where they form hunting associations. Each year, the hunters of each association agree on the hunting quota for their hunting area based on their perception of rabbit population quality. Decisions on hunting quotas move between two contrary attitudes: to conserve rabbit population for coming years, limiting hunting activity, or to hunt the greatest number of animals, without any restriction on hunting activity. However, no information is available on the hunting quotas applied by hunting associations.

Governmental policies on the timing of rabbit hunting in Spain have not changed at least since 1902 ([B.O.E., 1970]). These policies probably were established as rabbit control measures in response to huge economic losses in agriculture due to rabbits. However, since the sharp decrease in rabbit abundance, damage to crops has become sporadic and the timing of the rabbit hunting season in Spain has been maintained more for historical reasons than to protect agricultural assets. This also occurs in other southwestern European countries such as Portugal and France ( [REGHAB, 2002]). It would be advantageous to be able to predict the level of hunting that current rabbit populations can support, and when hunting should be applied so as to ensure the smallest impact on rabbit populations while maintaining hunting activity.

Rabbit population models have been used to increase knowledge regarding the efficacy of different management strategies aimed primarily at rabbit control. These include general models on unspecific control strategies ([Darwin and Williams, 1964, Smith and Trout, 1994 and Smith, 1997]) and, more recently, models in which disease is the control method ( [Pech and Hood, 1998 and Hood et al., 2000]). However, models focusing on rabbit conservation have received little attention ( [Calverte and Estrada, 2000 and Fa et al., 2001]). All rabbit population models developed to date have been based on parameters obtained from populations outside of the original range of rabbits (i.e. [Smith and Trout, 1994]). It is well known that there are ecological differences between rabbits throughout Europe, including a latitudinal trend in reproductive parameters and differences in survival and mortality ( [Rogers et al., 1994]). Additionally, genetic analyses have revealed differences between southwestern European rabbits and rabbits from other regions ( [Monnerot et al., 1994]).

Use of ecological models developed in other areas to assess the timing of rabbit hunting in a particular area, southwestern Europe in the present case, should be undertaken with prudence when interpreting model results. Previous rabbit models have explored the optimal timing to carry out population control in wild rabbit populations in New Zealand ([Darwin and Williams, 1964]) and England ( [Smith and Trout, 1994 and Smith, 1997]). These models suggest that control should be applied when the population is naturally declining and each female killed reduces overall reproductive capacity for the next season. Applying these results to southwestern Europe, and disregarding differences in the demographic parameters, we can hypothesise that the current Spanish hunting period coincides with the best population control period.