Analisi dei fattori di disturbo nelle aree di alimentazione del chiurlo maggiore Numenius arquata in un sito di svernamento dell’Italia centrale

Abstract

From 1997-2001, I investigated the effect of disturbance factors on feeding behaviour of the curlew Numenius arquata in a coastal region of Lazio (Pontine Lakes). Recreational activities (mainly mountain biking, birdwatching and hiking) and predators were the main causes of disturbance. Shooting, right beside the protected area where the curlews fed, was also a cause of an escape response. The birds were much more likely to return to the feeding patch when the disturbance was natural (e.g., intraspecific aggression or predators passing close by) than when it was caused by man. Although not frequently occurring, ultra-light aircrafts and motorized delta-planes that flew over caused a strong alarm response among curlews and always drove them to abandon the feeding area. Strong alarm response and leaving the feeding sites for other distant areas were also the reactions of birds foraging in areas beside roads when hikers, cyclists or birdwatchers passed close by. To prevent all these disturbance effects on the feeding activity of curlews, good conservation practices might be to ban over-flying on sensitive areas, to create buffer zones along the edge of the protected area and to install plant screens along the roads. These management actions would reduce visual and acoustic impact and finally allow the curlews to fully enjoy an undisturbed foraging within a protected area.