Common Swift Welfare: Breeding Colony Decline and Urban Challenges

Common swifts face rapid population decline linked to loss of nest sites in older buildings, climate impacts on aerial invertebrate prey, and migration hazards.

Key Facts

UK swift populations declined by over 50% between 1995 and 2022
Swifts are almost entirely aerial, feeding, sleeping, and mating on the wing
They return to the same nest site for decades; loss of one building can eliminate a colony
Swift nests are found in gaps in building soffits, behind render, and under roof tiles
Poor summer weather and reduced aerial insect abundance both reduce breeding success

Welfare Considerations

Swifts that lose nest sites through building renovation may return repeatedly to inaccessible sites, expending energy and showing stress behaviours before being displaced. Chicks that fledge too late due to poor prey availability face starvation during migration. Individuals grounded due to weather or injury are highly vulnerable as they cannot take off from the ground. The UK planning requirement for swift bricks in new buildings is a positive welfare measure. Chronic decline in aerial invertebrate abundance due to pesticide use and climate change represents the most intractable long-term welfare driver.

What You Can Do

Install swift nest boxes or swift bricks on suitable buildings before swifts return in May
Retain all existing swift nest sites during building renovation and refurbishment
Support planning policies requiring swift bricks in new buildings
Create insect-friendly gardens to support aerial invertebrate prey populations