This study was supported by the"Gioia and Carlo"Foundation. We want to thank the Veterinarian Renato Ceccherelli and its staff at the Centro Recupero Uccelli Marini e Acquatici(CRUMA-LIPU),for the important assistance and support provided during ringing activities at the nest.All volunteers from the Gruppo Ornitologico Maremmano(GOM)who took part in field surveys and helped in detecting Montagu's Harriers activity areas are also deeply acknowledged.FM was funded by EU-Next Generation EU Mission 4"Education and Research"-Component 2:"From research to business"-Investment 3.1:"Fund for the realization of an integrated system of research and innovation in-frastructures"-Project IR0000032-ITINERIS-Italian Integrated Environmental Research Infrastructures System-CUP B53C22002150006.The author acknowledges the Research In-frastructures participating in the ITINERIS project with their Italian nodes:ACTRIS,ANAEE,ATLaS,CeTRA,DANUBIUS,DISSCO,e-LTER,ECORD,EMPHASIS,EMSO,EUFAR,Euro-Argo,EuroFleets,Geoscience,IBISBA,ICOS,JERICO,LIFEWATCH,LNS,N/R Laura Bassi,SIOS,SMINO.The authors are grateful to A.E.Schlaich and other three anonymous reviewers for their valuable suggestions on a previous version of the manuscript. （CRUMA-LIPU）