Shall we go to the mountains or to the sea for the winter holidays? Occurrence drivers and cultural relevance of the climate-vulnerable Snow Bunting Plectrophenax nivalis in Italy

Abstract

The non-breeding distribution and ecology of many migratory songbirds are often poorly studied, but very relevant for their conservation in a changing climate. The Snow Bunting is the most northerly breeding passerine worldwide, and winters in temperate/temperate-cold areas. Characterised by specialisation for cold climate and strong migratory connectivity, it underwent a recent range contraction and is declining because of rising winter temperatures. Investigating its migration and wintering distribution and ecology is relevant to understand the possible impacts of climate change. We used citizen science records to describe and model the species distribution during migration and winter in Italy, and evaluated its cultural relevance. Snow Buntings occur in Italy in November-mid April, mostly clustered in northern and, particularly, north-eastern regions (coasts and plateaus in mountain regions); all the observations involving >12 individuals occurred at a single site in the Lessinia plateau. The elevation pattern of observations (both during winter and migration) showed a bimodal distribution (mostly at the sea level and in middle-elevation mountains, peaking around 1500 m asl). Species Distribution Models showed that the most suitable areas largely coincide with the areas from where most observations occurred, and were similar during winter and migration. Such areas are characterised by relatively cold and dry climates, and by flat or gentle sloping terrain largely occupied by open or semi-open habitats (grassland, pastures, sandy habitats). Snow Buntings had a much higher occurrence rates in social media/networks than other bunting species, indicating that nature recreationists have a particular preference for this species, which can be used as a flagship species. The species will likely suffer from ongoing climate variation, and preserving suitable open landscapes, with grassland-dominated habitats, is key to the maintenance of suitable stop-over and wintering sites. At the same time, this would also benefit many declining breeding species.