Animals may perceive humans as a form of predatory threat, a disturbance, triggering behavioral changes together with the activation of physiological stress responses. These adaptive responses may allow individuals to cope with stressful stimuli, but a repeated or long-term exposure to disturbances may have detrimental individual- and population-level effects. We studied the effects of human activities, particularly hunting, on the behavior and physiological status of a near-threatened nongame steppe bird, the little bustard. Using a semiexperimental approach, we compared before, during, and after weekends: 1) the type and intensity of human activities and 2) the behavior and 3) physiological stress (fecal corticosterone metabolites) of wintering birds. Higher rates of human activity, in particular those related to hunting, occurred during weekends and caused indirect disturbance effects on birds. Little bustards spent more time vigilant and flying during weekends, and more time foraging in the mornings after weekend, possibly to compensate for increased energy expenditure during weekends. We also found increased physiological stress levels during weekends, as shown by higher fecal glucocorticoid metabolite concentrations. Increased corticosterone metabolite levels were associated with the highest levels of hunting-related disturbances. Little bustard showed marked behavioral and physiological (stress hormones) responses to human activities that peaked during weekends, in particular hunting. The long-term effect of this particular activity carried out during weekends from autumn throughout winter might adversely impact wintering populations of this nongame endangered species, potentially counteracting conservation efforts conducted on local as well as foreign breeding populations.
SUMMARY: European agricultural landscapes hold important endangered and game species, which may add socioeconomical and ecological value to the ecosystem, and thus must be considered priority species in any management programme integrating agriculture, hunting and conservation. Patterns of red-legged partridges (Alectoris rufa) nesting habitat selection and nesting success provide information for the implementation of these kinds of programmes in agrarian pseudosteppes. Nests occur mainly in cereal grain fields, although this habitat type was overall negatively selected and had the lowest nesting success. Only lindes (herbaceous strips among fields) were positively selected, and were also the habitat type with the highest nesting success. Nests within cereal grain fields were positively selected close to the field margins (mostly < 5 m). Agricultural practices, particularly harvesting, were the main cause of nest failure. Changes in agricultural practices would be a more effective means of increasing nesting success than predator control. Partridge breeding success may be improved by better management of agricultural areas, increasing the availability of lindes and slightly delaying cereal harvesting. These data may have implications for other endangered steppe-birds with similar nesting habitat, and may provide the basis for effective and successful collaborative programmes between hunters and conservationists.
Hunting is one of the human activities that directly affect wildlife and has received increasing attention given its socioeconomic dimensions. Most studies have been conducted on coastal and wetland areas and showed that hunting activity can greatly affect bird behaviour and distribution. Hunting‐free reserves for game species are zones where birds find an area of reduced disturbance. We evaluated the effect of hunting activities on the behaviour and use of hunting‐free areas of lapwings Vanellus vanellus, golden plovers Pluvialis apricaria and little bustards Tetrax tetrax in agricultural areas. We compared the habitat use and behaviour of birds on days before, during and after hunting took place. All three studied species showed strong behavioural responses to hunting activities. Hunting activity increased flight probability and time spent vigilant (higher on hunting days than just before and after a hunting day), to the detriment of resting. We also found distributional (use of hunting‐free reserve) responses to hunting activities, with hunting‐free reserves being used more frequently during hunting days. Thus, reserves can mitigate the disturbance caused by hunting activities, benefiting threatened species in agricultural areas. Increasing the size or number of hunting‐free areas might be an important management and conservation tool to reduce the impacts of hunting activities.
9 October 2007 in Behavioral Ecology and Sociobiology