Scientific publications

In open-nesting passerines, nest predation is the most significant and variable factor limiting breeding productivity. Predation on Redwing Turdus iliacus nests in the Kivach Nature Reserve (southern Karelia) was analyzed of the 1972–2024 period (771 nests in total). Due to the species' long breeding season and high interannual variability of spring temperatures, the conditions for breeding at different nests are highly variable. The MARK program was used to compare daily nest survival models. The hypotheses tested included constant nest survival, its dependence on calendar dates, nest age (number of days since the onset of egg laying), and spring characteristics in the breeding year. The average May temperature and the date of average daily temperatures steadying above +5º were used as the spring characteristics. The data provided the greatest support for the model of nest survival additive dependence on calendar dates and average May temperature, while nest age had no effect. Nest survival increased rapidly from early to mid-season; further changes were insignificant. According to the best model, overall survival for nests with the onset of egg laying on May 10 was 1.7 times lower than for nests with the onset of egg laying on June 15 (25.1 % and 43.2 %, respectively). High May temperatures enhanced nest survival. Determining the mechanisms behind the observed relationships requires further research, but the most likely explanation is an increase in the abundance of alternative prey and improved nest camouflage towards the summer, to which high May temperatures contribute.