Nest boxes offer declining common swifts a place to breed

Common swifts have been recorded in record numbers this summer, but the data does not yet indicate that the species is recovering, Yle reports. The bird, which is BirdLife Finland’s bird of the year, has declined sharply, with its population falling by tens of per cent each decade.

Risto Willamo, a docent in environmental sciences at the University of Helsinki, has nine pairs nesting in boxes on the gable wall of his house in the village of Meltola in Raasepori, western Uusimaa.

“This colony has probably been here for at least 50 years,” Willamo said. “We added one new box this summer, and it was occupied immediately.”

Birdwatchers across Finland have collected an unusually large number of swift observations during the bird’s themed year. BirdLife’s bird of the year project gathers enhanced information on a species’ condition and supports its protection.

The large volume of observations will help researchers refine estimates of the swift population, according to Aapo Salmela, a conservation specialist at BirdLife Finland. The information can also help identify important nesting sites to local birdwatching organisations.

However, the data requires further analysis before it can show whether the population is recovering.

Common swifts still breed in relatively large numbers in the centres of Lohja, Karjaa and Tammisaari in western Uusimaa. Although the species remains fairly common, its population is declining rapidly.

The reasons for the decline are not fully known, but a shortage of nesting places is one of the species’ biggest problems. Modern buildings and roof structures are often so tightly sealed that there is no room for the birds.

Common swifts need nesting sites high above the ground because they drop onto their wings before taking flight. Willamo encourages housing companies and private individuals to install swift nest boxes on exterior walls.

The boxes should be placed at least four metres high, and preferably six metres, with as much open flying space in front of them as possible. A box does not necessarily attract a bird during its first summer, but the chances increase the following year.

The swifts have already left for the season, but nest boxes can be installed now in preparation for next year. According to Willamo, the birds leave very little mess behind and can also safely be allowed to nest in building structures.