1. L. Rotelli, Via Valverde 98, Varese, Italy.
2. R. Bionda, Aree Protette dell'Ossola, Varzo (VB), Italy.
3. N. Zbinden, Surenweidpark 10, Oberkirch, Switzerland.
4. M. Schaub (https://orcid.org/0000-0003-2745-0557) ✉ (), Swiss Ornithological Inst., Sempach, Switzerland.