House sparrows are small, highly adaptable birds that readily nest in dryer vents, signage, gutters, and gaps under eaves. Their nests, built from grass, feathers, and debris, can block ventilation and drainage if left in place.
They are also known to be assertive around outdoor dining areas and bird feeders, competing with native species for nesting sites. Capping vents and sealing small gaps in the building envelope before nesting season begins is the most effective way to prevent them from moving in.