With the summer´s approach we start seeing again swalows in the small towns in Belgium. For example where I live there are many houses with both swalow and man-made nests under the roofs which are every year used by the swalows. I always wonder whether the same families come back every year to nest. Most likely they do since they are skilled migrators.
The preferred habitat of the Barn Swallow is open country with low vegetation, such as pasture, meadows and farmland, preferably with nearby water. This swallow avoids heavily wooded or precipitous areas and densely built-up locations. The presence of accessible open structures such as barns, stables, or culverts to provide nesting sites, and exposed locations such as wires, roof ridges or bare branches for perching, are also important in the bird's selection of its breeding range.
The male Barn Swallow returns to the breeding grounds before the females and selects a nest site, which is then advertised to females with a circling flight and song. The breeding success of the male is related to the length of the tail streamers, with longer streamers being more attractive to the female. So the "peacocks tail" theory holds true for the barn swalow!