1. a State Forestry Agency, Department for Biodiversity , 67100, L'Aquila, Italy
2. b Ornis italica , Piazza Crati 15, 00199, Rome, Italy
3. c ISPRA – ex INFS , Ca' Fornacetta 9, Ozzano Emilia, Italy
4. d National Park “Gran Sasso e Monti della Laga” , Wildlife Research Centre , 67100, Camarda, Italy