Seasonal changes of bird assemblages in a small urban wetland revealed by mist-netting

Seasonal differences of bird assemblages were studied using mist-netting method during four seasons (May, July, September, and December) in two years (2014 and 2021) in a secondary wetland habitat (7 mist-nets in willow grove, reed, and scrubland) in Zvolen town, central Slovakia. Altogether 54 species and 876 individuals of birds were captured during 24 days of eight trapping sessions (in 84 m of mist-nets at 7.3 ha study plot). The highest number of mist-netted species and individuals was found in July (36 species, 290 individuals), the lowest was in December (16 species, 153 individuals), pooled for both years. The most abundant species were breeding species Sylvia atricapilla, Parus major, Cyanistes caeruleus and Turdus merula. The characteristic reedbed birds included four Acrocephalus species, Locustella luscinioides, Emberiza schoeniclus, and scrubland species Luscinia megarhynchos, Sylvia communis and Remiz pendulinus. Seasonal differences in species number and abundance are discussed. Regular wintering was found in migratory species Prunella modularis and Erithacus rubecula north of the known winter quarters of their central European breeding populations. The site fidelity and between-season retraps were confirmed in 10 species and 54 individuals (18.5% of all mist-netted species and 6.2% of all individuals). Based on retrapped individuals, the resident species P. major, C. caeruleus, Aegithalos caudatus and T. merula were the most faithful to the site, whereas inter-seasonal retraps of migratory species were rare (e. g. Sylvia atricapilla, Luscinia megarhynchos and Phylloscopus collybita).