Early-succession secondary forests following agropastoral abandonment are key winter habitats for the conservation of a priority bird in the European Alps

In contrast to old-growth forests, early-successional stands remain understudied despite potentially harbouring species ofconservation interest. With this work, focused on hazel grouse Tetrastes bonasia, a cryptic and indicator species known toselect for close-to-natural forests, we evaluated winter densities, home range, microhabitat selection and diet, combiningDNA-based mark-recapture and metabarcoding from faecal samples. In total, 216 droppings, collected over 2 years alongforest transects in the Italian Alps, were successfully genotyped and 43 individuals were identifed. Density estimateswere similar to values reported by other studies in the Alps with an average of 4.5 and 2.4 individuals/km2 in the frst andsecond study year, respectively, and mean home ranges estimated at 0.95 km2. According to habitat selection models andeDNA-based diet analysis, hazel grouse selected early-succession secondary-growth forests formed after the abandonmentof traditional agropastoral activities. These forests, mostly composed of hazel Corylus avellana, Norway spruce Piceaabies and Sorbus spp., provided winter food resources and shelter. The diet analysis also highlighted forest arthropods as anon-negligible source of food. Birds avoided areas subject to intensive browsing by ungulates; small forest roads seasonallyclosed to trafc had positive infuence on hazel grouse (i.e. higher abundance of droppings), while roads open to trafc hadno efect. Importantly, despite the high coverage of mature forest habitats of Community Interest (53% of our study area),droppings were more abundant in non-listed early-succession secondary forests with similar plant composition. Our resultssuggest that forest succession after agropastoral abandonment may be benefcial for some forest birds of conservation interest, while acknowledging its negative efects on the previous grassland biodiversity