Swifts have adapted to nesting almost exclusively in buildings, but very occasionally nest in trees or caves. Basically they nest in suitable holes.
Swifts are known to return to the same site year after year (in some cases for hundreds of years) and their preference for site fidelity makes retaining existing nest sites a top priority in any project.
Generally swifts are dependant on small holes on the outside of a building giving access to a larger space within. They may rear young in the large open area provided by a loft, or in the small space provided between the tiles and the sarking, below tiles or by collapsed masonry inside a wall.
Most modern building methods take every precaution to ensure that there are no small holes or gaps and many modern materials (like plastics, metals and reinforced concrete) do not deteriorate to form suitable holes and gaps.
Swifts only nest in old buildings
No - they nest in buildings which have suitable nesting places. We are sure that some swift colonies in post-war buildings go unrecorded because people cling obstinately to the idea swifts only nest in really old buildings, and fail to explore later housing estates.
Swifts only nest in the urban environment
No - they are also recorded in remote places where there is only one building, and maybe one or two sites. Assume nothing; the assumptions are made by humans, not by swifts. While it seems to be true that they are attracted to the sound of other swifts, they also find nest sites in remote areas with no other swifts within calling distance.
Swifts nest in church towers
No - swifts do not naturally nest in church towers. They do swirl around towers as the updraughts caused by the building draw in the small insects/aerial plankton that swifts feed on, leading some people to believe they are nesting there. Known church tower sites are man-made.
Swifts only nest in sites over 5m above ground level
No - chosen height above ground level seems to depend on availability – with plenty of recorded sites being at 2 – 3m above ground level. More important is a clear flight path to the site.
Man-made swift nest sites
The following examples are nests in Scotland
In 19th century sandstone tenements, swifts often nest on the wall head, gaining access via gaps in stone and broken pointing.
In the 1930s onwards, roof tiles were sealed at the gable ends using mortar (tiffing). Over time the mortar wore away, leaving gaps and cracks where swifts got access to the small spaces under the tiles- probably no more than 50mm deep and on the batons.
There are miles and miles of estates built in this period and in this basic style. In many Scottish cities, swifts have moved into these schemes, which are now subject to wholesale renovation and demolition
The assumption that swifts nest in old buildings too often leads to these colonies being ignored – this style was used until the 1960s.
Behind the faschia on other elevations there was originally chicken wire to permit ventilation and prevent access by birds, but over time the chicken wire deteriorated, allowing access to the internal space for swifts (as well as sparrows and starlings too).
In older buildings – and more often seen on the continent, particularly in Holland, where the roofs are usually at a steeper 60 degree slope – swifts will get under slipped or broken tiles on the roof
If you have pictures of modern buildings with swifts nesting in them and are happy for them to be published on this website, send them to email@example.com with some basic information, property age, location and date of photograph.