The High Level of Between-Year Burrow Reuse in a European Bee-Eater Merops apiaster Colony

In this paper, we report a high level of burrow reuse by European bee-eaters (Merops apiaster) in a mixed colony shared with common starlings (Sturnus vulgaris) and common swifts (Apus apus) at Višnjička Kosa, a suburban area of Belgrade, Serbia. The study was conducted during the breeding season in 2023 and 2024. Of the 255 burrows examined in 2024, 123 (48.23%) had been used in a previous breeding year, 88 (34.51%) were completely or partially excavated prior to 2024 but not used in 2023 and 36 (14.12%) were newly excavated in 2024. These results demonstrate a substantial level of burrow reuse within the studied colony, suggesting that reusing existing burrows may allow birds to conserve the energy and time otherwise required for new excavation.