Doi: https://doi.org/10.13157/arla.72.2.2025.ra2
Authors: Dae-Han CHO, Ju-Hyun lEE, Myung-Bok lEE, Seung-Jun OH and Ha-Cheol SUNG
E-mail: shcol2002@chonnam.ac.kr
Published: Volume 72.2, July 2025. Pages 177-197.
Language: English
Keywords: artificial structure, Eurasian Tree Sparrow, nestling development, reproduction and urban area
Summary:
Rapid urbanisation represents a major threat to ecosystems and biodiversity but novel environmental factors that emerge in urban environments are often attractive to some species. In urban environments, new food sources are relatively easy to access during the winter season, leading to an improvement in the body condition of adult birds during the wintering and pre-breeding seasons. However, despite the positive effects urban environments have on birds, these areas can sometimes act as ecological traps, imposing constraints during certain energy-demanding periods. In this study, we investigated the effects of urbanisation on the reproductive performance and nestling development of Tree Sparrows Passer montanus, which are known urban exploiters, examining their urban adaptation based on the urbanisation score. we conducted the study across 12 sites that represent different levels of urbanisation, from April 1 to May 16, 2022, in Gwangju, Naju and Damyang in the Republic of Korea. We located three to 17 nests in each site and assessed breeding status and nestling development at four, eight, 12 and 15 days after hatching. We found that greater urbanisation was associated with later laying dates and lower clutch sizes. Nestling body condition tended to increase with urbanisation score on day four but decreased with increasing urbanisation scores on days 12 and 15. However, urbanisation did not affect tarsus lengths at any developmental stage. Overall, reproduction and nestling development were negatively affected despite the urban environment being attractive to the Tree Sparrow population. Thus, we suggest that urban areas may act as ecological traps for Tree Sparrows, but it will be necessary to analyse the ecological trap phenomenon in more depth in future studies.
