I passeri Passer  spp.: da “problematici” a specie diinteresse conservazionistico

Dinetti M.



Abstract:

The Sparrows Passer spp.: from “pest species” to species of conservation concern. The House Sparrow Passer domesticus is closely linked to human settlements, and it is probably the most widespread passerine worldwide. However, in the last few years this species has been declining throughout Europe, particularly in urbanized areas, so that this species is now considered of conservation concern (SPEC-3). The situation is complex and differ amongst town and between urban and rural environment. In Italy the Italian Sparrow Passer italiae occupies the same ecological niche, whereas in Sicily and Sardinia lives the Spanish Sparrow Passer hispaniolensis. The estimate for the breeding population of the Italian Sparrow ranges from about 5 to 10 million pairs, the one for the urban population in the Italian peninsula from about 750,000 to 900,000 pairs, with a density from about 58 to 160 pairs per square kilometer. The available data from national monitoring show a decrease in the population indices between 2000 and 2005: Italian Sparrow -27.1%, Spanish Sparrow -38.5%, Tree Sparrow Passer montanus -10.1%. For the last ten years, data show a decrease in the urban populations of the Italian Sparrow till 50%, and this confrms the situation reported for the House Sparrow elsewhere in Europe. We discuss the possible causes of the decline that have been suggested so far both for Italy and for Europe: in rural areas mainly agricultural intensifcation; whilst in towns there are more potential reasons: food shortage (particularly insects to raise nestlings) in relation to reduction of green areas and to air pollution, reduced availability of suitable breeding sites, increased predation, competition for food with Feral Pigeons Columba livia forma domestica and other species, road mortality, window collisions, etc. The decline of common species should be of concern for conservation science. We suggest a monitoring programme with standardized census methods (territory mapping with plotting on 1:2000 scale maps, quantitative urban bird atlas, line-transect lasting 30 minutes) be used by ornithologists, birdwatchers and citizen scientists. Sparrows are an umbrella species with a strong appeal to the public, and are good indicators of the quality of the urban environment, the habitat in which most of us now live.