Funding for this research was provided by:
Nemzeti Kutatási Fejlesztési és Innovációs Hivatal (EFOP-3.6.1-16-2016-00022)
Hungarian Scientific Research Fund (K112527)
Ministry of Innovation and Technology (NKFIH-1150-6/2019)
Magyar Vidékért (Pro Regione) Foundation
Received: 4 November 2020
Revised: 31 December 2020
Accepted: 5 January 2021
First Online: 26 January 2021
Compliance with ethical standards
: The authors declare that they have no conflicts of interest.
: Tree sparrows were ringed under a licence from the Hungarian Bird Ringing Center (licence nr. 390 accredited to ZB) and permission for the study was granted by the Hajdú-Bihar County Governmental Office, District Office of Debrecen - Department of Environmental and Nature Protection (permit nr. HB/10-KTF/00487-1/2016). The study complies with the European laws regarding animal welfare and adheres to the ASAB/ABS guidelines for the use of animals in behavioural research.