Commensal nesting of White Storks (Ciconia ciconia), Spanish Sparrows (Passer hispaniolensis) and house sparrows (Passer domesticus)

). The study revealed a significant number of eggs and nestlings of both sparrow species, alongside high losses due to mechanical damage and adverse environmental conditions. The results highlight the White Stork's role as an "ecosystem engineer" fostering urban biodiversity through synanthropic habitats, where sparrows commonly nest in stork structures. Analysis of the nest contents further quantified the high reproductive density within these structures, while also identifying significant mortality factors. Ultimately, the study concludes that stork nests serve as critical biodiversity hotspots in anthropogenic landscapes, providing essential nesting niches that support large, multi-species sparrow colonies. These findings underscore the importance of integrating conservation strategies for "engineer" species into rural infrastructure management to preserve these accidental, but vital ecosystems.