For migratory species such as swallows and swifts destruction of just one of their habitats would have a drastic effect.
The Royal Society for the Protection of Birds (RSPB) report that swift numbers have declined significantly over the past 10 years. A survey of 3,400 swift nests in the UK found that nearly 80 per cent were on houses, mostly those built before 1919. About 5 per cent of swift nests were in churches. The swifts use holes high up in these buildings so they can launch themselves when taking flight. Swallows have similar habits, but they tend to nest in barns and old outhouses, especially where there are manure heaps close by which attract insects.
Swifts and swallows have a summer breeding season in the northern hemisphere where they take advantage of the huge supplies of insects. The birds tend to return to the same nesting sites each year. The RSPB swift survey found that just over half (52 per cent) of the swift nest sites had been in use for at least 10 years.
In the UK, conversion of old houses, barns and derelict farm buildings into luxury homes has reduced potential nesting sites for swallows and swifts. Removal of manure heaps that were close to old barns before conversion, have reduced the supply of insects.
A nest of young swallows
In autumn the adult swifts and swallows and their mature young undertake a long migration to Africa where there are plenty of insects available. The migration is hazardous, as the birds face not only storms but also many are shot as they fly over some southern European countries. In Africa, development has resulted in habitat changes that affect the overwintering sites of swallows and swifts. In order to conserve migratory species it is essential to consider both winter and summer areas and also to safeguard the birds’ sources of food.
More information on swifts and their habitats can be found on the RSPB website.
How you can help
The RSPB point out that both new houses and converted old buildings can be designed to provide potential nesting sites for swifts and swallows. Residents who plant flowers and shrubs, and limit use of insecticides, encourage insects, which are important food for birds. Insects are also important for pollinating food crops such as fruit and vegetables, so planting flowers and shrubs creates many benefits linked to biodiversity.