Context. Ecotourism and human recreational activities are increasing and can have a significant impact on fauna. The analysis of faecal glucocorticoid concentrations is a non-invasive method of measuring physiological stress responses of wildlife to various factors (i.e. human disturbances).

Aims. The aim of the present study was to determine whether increased physiological stress levels in wildcats (Felis silvestris) were a response to the level of tourism allowed within different zones in a natural park and/or a response to the seasonal reproductive state of wildcats.

Methods. The study was conducted from May 2005 to June 2009 at the Natural Park Montes do Invernadeiro (north-western Spain). The Natural Park is divided into the following three zones according to the level of tourism allowed: restricted public-use, restricted zone and integral reserve. An enzyme immunoassay technique was used to quantify cortisol metabolites and sex hormones from each of 110 fresh wildcat faecal samples collected from walked transects on forest roads within each zone. The number of visitors was recorded as a measure of tourist pressure.

Key results. The general linear model indicated that park zone and faecal progesterone levels were the factors that explained the variation in the faecal glucocorticoid metabolite levels. Cortisol metabolite concentrations were higher in some park zones where tourism intensity was higher (restricted public-use zone). Faecal cortisol metabolite concentrations were more elevated during gestation (spring) and during the young dispersal period (autumn).

Key conclusions. Therefore, we recommend that some zones of park (integral reserve) continue being maintained free of visitor impact and that visitor numbers be specially controlled during the animals’ sensitive periods (gestation) in the zone of restricted public use and in the restricted zone.