Study site
This project was conducted under research permits from the Tanzania Wildlife Research Institute (TAWIRI) and the Tanzanian Commission for Science and Technology (COSTECH), permit no. NA-2019-85. I conducted field observations in Mbeya and Iringa region, Tanzania, during the rainy season from March to May 2019, when cordon-bleus usually start pairing and breeding (Goodwin 1982). The recording of the nests was performed while conducting the field observation of courtship display in cordon-bleus (Ota 2020).