Window-mounted bird houses in these listings are small, typically about 5–6 inches long, roughly 3.8–8.5 inches wide, and about 8.25–9.25 inches high.
Many small bird houses include slide-out panels or cleaning doors and recommend spot-wiping or rinsing. Nesting boxes and larger units often provide removable or pull-out trays to enable more thorough washing.
Smaller nest boxes and window-mounted houses are intended for small songbirds such as wrens, chickadees, warblers, finches, and sparrows.
It varies: some small bird houses require no assembly, while larger coops and cages typically need adult assembly and may or may not include tools; some larger enclosures advertise tool-free or color-coded snap-together assembly.
Common features include a sloped, roll-away floor that guides eggs into a front collection tray, multiple private compartments, removable trays, and drainage holes to keep eggs clean and simplify washing.