Phenological changes in arrival and breeding in common swifts (Apus apus) in central Israel

This study examines phenological shifts in arrival dates of common swifts (Apus apus) in Givatayim, central Israel, from 2015 to 2023. Utilizing data from closed-circuit television (CCTV) camera footage in urban nest boxes, we observed a significant advancement of 16 days in the species’ arrival from 2015 to 2023. Our methodological framework involved monitoring dates of the swifts first (FAD), second, and median arrival dates, followed by statistical analyses to reveal temporal trends. We discovered a strong relationship between FAD and subsequent breeding milestones, such as egg laying, hatching, and fledging period, clarifying the potential impact of early arrivals on common swift reproductive timing. Phenology showed no relationship with temperature in early spring. Our results confirm the results of previous studies on other species, i.e. that common swifts are arriving earlier at their breeding grounds in central Israel.