Episod 8: The common swift
Who is screeching high above the city in the summer sky?
With the new ” Lend an ear to nature” campaign, the Mouvement Ecologique wants to draw attention to these often-threatened species and their habitats – and combine it with a guessing quiz on the noise of the animal in question.
A total of two short videos on a species of animal from our localities and landscapes will be published each month from the end of April until October.
Guess with us – which animal is making that sound? and win a Naturata voucher worth €50 per spot!
© Billy Lindblom, CC BY 2.0
Did you recognise the common swift in the clip?
‘Sriiih-sriiih’… This shrill call belongs to the common swift – and inevitably evokes feelings of summer.
Many people associate these calls with balmy summer evenings on a terrace in the village or town, from where you can watch the flocks of swifts performing acrobatic manoeuvres around a church tower – an aerial show accompanied by a concert, so to speak. Swifts are migratory birds and only visit this country for a very short time – from the beginning of May to the beginning of August.
The swift is called ‘Leeëndecker’ in Luxembourgish. It owes this name to its typical breeding behaviour: it seeks out crevices under eaves or between masonry and roof tiles as a breeding place – often high up on buildings.
But be careful: many people confuse it with a swallow. Although their silhouettes are similar – both bodies have evolved to be optimally suited to hunting insects in flight – the two belong to completely different groups of birds. Swifts have longer wings and a ‘sickle-shaped’ silhouette.
Way of life
The ‘Leeëndecker’ seeks out crevices under eaves or between masonry and roof tiles as breeding sites – often high up on buildings. Its ‘nest’ is usually just a loose pile of feathers and plant parts that it collects in the air while flying.
A very remarkable fact about the common swift is that it spends almost its entire life in the air – it is virtually a flying wonder! It only lands to breed, otherwise it is always in the air. Its legs are so short that it cannot walk on the ground, but they are long enough to cling to vertical walls or rocks.
They even sleep in flight – at altitudes of 1,500 to 2,500 metres! When they have chicks to feed, they spend up to 18 hours a day hunting insects. They cover enormous distances, sometimes more than 900 km a day, to collect food such as mosquitoes, flies and aphids. A ‘mouthful’ can consist of 300 to 1,500 insects – 1 to 2 grams of concentrated protein for the hungry young.
If the weather is bad or it gets colder, the young birds fall into a kind of energy-saving state, known as starvation sleep or cold torpor. This allows them to survive for several days without food until their parents – often far away – return with fresh prey. In France, the swift is also called ‘Hirondelle de pluie’ (rain swallow) because large flocks hunt insects in low flight when the weather changes – a sign of approaching rain.
After about three months – around the beginning of August – the young birds are ready to fly and follow their parents south. The journey takes them as far as South Africa, where they spend the winter.
Threats to the common swift
The common swift is becoming increasingly rare in our settlements – the main reason being the “housing” shortage. Modern buildings no longer offer any crevices or cavities where it can lay its eggs. Old cracks in walls, which used to be ideal nesting sites, are now mostly plastered or sealed. Even the smallest gaps under the eaves are closed during renovations.
What’s more, renovation work during the breeding season can wipe out entire colonies. Insect decline also has an indirect impact – less food means lower survival rates for the young. Extreme weather conditions such as long periods of rain are leading to increasingly frequent breeding losses.
Distribution in Luxembourg
The common swift can be found in many Luxembourgish towns and villages – but only where there are still suitable breeding sites. It is particularly active in older buildings with traditional roof shapes. Luxembourg lies on the northern edge of its Central European breeding range.
The common swift is on Luxembourg’s red list of endangered bird species because its population is declining sharply.It is listed in the ‘near threatened’ category.
© XJochemx.nl, CC BY-SA 4.0
How can I help the common swift?
- Create nesting sites in existing and new buildings:
Install special nesting boxes for common swifts – at least 5 metres high, protected from rain and with an unobstructed approach. For new buildings, there are also specialized façade stones with integrated breeding chambers that can be installed.
- Preserve nesting sites:
Plan renovations outside the breeding season, which lasts fromlate April to early August. Leave existing breeding crevices open if possible (install scaffolding and dust nets accordingly) or replace them with substitute quarters.
- Promote insect diversity:
Design your garden to be close to nature – with native wildflowers and shrubs, without pesticides – and support organic farming through your consumption.
- Report and get involved:
Share your observations with local species conservation initiatives such as SICONA or Natur&Ëmwelt. Approach your local council to ask them to install nesting boxes for building-nesting birds on their buildings.
For more information on swifts and protection measures, as well as advice, see here:
SICONA Luxembourg: Swift project, https://sicona.lu/mauersegler-2/ (in German)
Natur&Ëmwelt: Urban birds project, https://www.naturemweltasbl.lu/urban-birds/ (in French)
LBV Munich, detailed information on species protection on buildings, https://www.lbv-muenchen.de/unsere-themen/artenschutz-an-gebaeuden/schutzmassnahmen/ (in German)