Common Swift

Apus apus

Although only with us for about three months each summer, Common swifts are familiar birds renowned for their wild aerobatics and shrill screaming in the open skies above towns and cities. They do everything, except nesting and raising young, on the wing. Numbers have shown dramatic declines in recent years, probably because of a loss in traditional nest sites when old buildings are demolished or renovated and new ones are built without suitable spaces. Latest figures from the Breeding Bird Survey show number of swifts fell by 42% in Scotland between 2011 and 2012. This is the third annual decline in a row and follows a 57% decline in Scotland since the mid-1990s[1].

Common swifts are now on the amber list of conservation concern. Swifts are protected under the Wildlife and Countryside Act of 1981, which makes it illegal to knowingly destroy or disturb the nest site during the nesting season. The Swift is on the list of Scottish priority species.

Description

Adult Common swifts are sooty-brownin colour with a small off-white throat patch. However, theyusually appear black in flight. Juveniles are dark black, except for white fringes on the forehead and a larger, well-defined white throat-patch. The tail is deeply forked and the sickle-shaped, sharply-pointed wings are narrow but long, enabling it to make rapid, sharp turns in the air whilst hunting flying insects. The feet are specially adapted to grasp onto vertical surfaces, meaning that it can utilise habitats like chimneys and building eaves forroosting and nesting.

Common swift ©Stefan Johansson

Distribution

The Common swift breeds in Eurasia and North West Africa and winters in tropical and southern African countries. It is a common summer visitor throughout the UK, but is most frequent in the south and east of England and absent from the Northern and Western extremes of Scotland. There are about 85,000 breeding pairs in the UK[2].

Distribution of Common swift in Britain and Ireland(From NBN gateway, accessed 10/10/13)

Ecology

Common swifts are summer visitors to Britain, arriving in Scotland from Africa in the first or second week in May and leaving in August[3]. Traditionally they would have nested in holes in caves or tree hollows, but nowadays they mostly use holes in walls or a free space under the eaves of houses. Theyuse the same nest year after year, merely adding fresh material which they catch on the wing. Pairs may breed together for many years, though if one partner dies its place will be immediately taken by another bird. Two to three eggs are laid and both parents broodthe clutch and care for the chicks. The young fledge after about 40 days. They need no exercises in flying and once they have left the nest they will never return. The first two or three years is spent in constant flight beforethey pair up to breed.

Threats

Natural predators include hobbies and sometimes small mammals which hunt in theroof spaces where they nest. They can be killed by collision with cars, particularly during rainy weather when the birds fly low. However, it is a reduction in the availability of food and nesting sites that are the greatest threats to Swifts

Modern building techniques and materials deny the Common swift access to eaves and wall cavities for nesting that they would have used in the past. Generally Swifts are dependent on small holes on the outside of a building giving access to a larger space within. 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 gaps. In addition, a tendency to demolish or refurbish old buildings such as warehouses and factories, which are often converted to modern apartments, also leads to a loss of nesting sites[4].

Management

Thoughtful urban planning is essential for effective Swift conservation, and these birds should be included in Local Biodiversity Action Plans. Homeowners and building developers can, with little effort or cost, help to maintain swift populations in urban areas. Where there is a known colony, the following actions,in order of effectiveness, should be considered[5]:

  • Leave the nests alone
  • Make new holes to retain access to nesting areas
  • Useinternal spaces to create new nest sites
  • Create new internal spaces
  • Use externally-fitted nest boxes
  • Urban green spaces that are used as feeding areas for swifts should also be protected from development.

Current work

Concern for Swifts (Scotland)5

Over 20 years Concern for Swifts (Scotland) (CfS) has had a significant positive impact on Common swift conservation action in Scotland. The project aims to have Swift nest site conservation incorporated into building specifications for new buildings, and refurbished buildings where appropriate. It collects records of Swift populations and nest sites and supports the inclusion of the Swift in Local Biodiversity Action Plans as an important indicator of a sustainable built environment and accessible wildlife. Actions have included producing information leaflets, making information available online, working with various organisations to provide examples of good practice for local authorities and conservation organisations to follow.

Swift Conservation[6]

Swift Conservation is a not for profit service providing free advice to individuals. They also provide a commercial service for building professionals. They advise on how to incorporate Swift (and some other bird and bat) nest places into buildings, improve biodiversity with cost-effective features, and meet local Planning requirements.

The Scottish Swifts’ project[7]

The RSPB runs a Swift nest survey encouraging people to look out for breeding Swifts either by identifying low-levelscreaming groups of swifts (that means they're breeding nearby) or those entering a roof or hole in a building.

Wider context

Like the Common swift, a number of other bird species including Swallows, House martins, House sparrows and Starlings have suffered population crashes during recent decades. These speciesoften rely on buildings for their nest places.

The Common swift is a familiar bird and can be seen in both town and country. Their almost exclusively aerial lifestyle makes them both unusual and fascinating and therefore a good Flagship species for the built environment.

Quick Facts

  • The UK's Swifts have one of the longest migration journeys in the World: 22,000 kilometres (14,000 miles) every year.
  • It is estimated that Swifts fly an averagedaily total of 800 km - nearly 500 miles.[8]
  • Ringing evidence confirms that a young Swift can be hundreds of miles southwards on its first trip to central African winter quarters within 48 hours of leaving the nest.
  • The oldest reported ringed bird was 21 years old, but theaverage life span is about 7 years.
  • It can survive bad weather by entering torpor, in which its metabolism slows to almost nothing.
  • In Gaelic it is known as Gobhlan-mòr.
  • There have been man-made swift nest-sites in the past.Perhaps the first swift nest site project was in Tuscany, where a tower was built specifically to attract Swifts so that the young could be harvested for food!4
  • The Swift is able to live a perpetually aerial life by sleeping with half of its brain at a time.[9]
  • The common swift performs most activities in the air, including feeding, preening, playing, sleeping and mating. It is the only bird known to mate on the wing.

Selected References

Accessed 10/10/13

Accessed 10/10/13

Eaton, M.A., Brown, A.F., Noble, D.G., Musgrove, A.J., Hearn, R.D., Aebischer, N.J., Gibbons, D.W., Evans, A. & Gregory, R.D. (2009) Birds of Conservation Concern 3: the population status of birds in the United Kingdom, Channel Islands and Isle of Man. British Birds 102: 296–341. (BoCC3)

Ulrich Tiggers 1997-2012)Accessed 10/10/13

Contains information about the Common swift in a worldwide context. Also has information about and links to academic research.

Wilson, J.S. (2012). Action to halt the decline of swifts in Scotland

An account describing how past and ongoing action across Scotland is helping both to protect Common swift nesting sites and to provide new sites to compensate for loss of nesting habitat. This account describes how action has been taken up to 2012 in various areas of Scotland to protect Common swift nesting sites and provide new sites to compensate for loss of nesting habitat.

(This information is also published in similar format as: 2011, Ecologia Urbana special issue 2/2011 and 2011 APUSlife, No. 4784)

[1] 12/12/13

[2] Accessed 10/10/13

[3] Accessed 10/10/13

[4] Accessed 10/10/13

[5] Accessed 10/10/13

[6] Accessed 10/10/13

[7] Accessed 10/10/13

[8] Accessed 10/10/13

[9] Accessed 01/10/13