Barn Swallow migration patterns on the move

16 November 2011

Barn Swallow A new paper in the top Royal Society journal, "Proceedings of the Royal Society B," looks in detail at how the timing of migration in three regions of South Africa is changing with the climate.

Swallows, delicate birds which breed in Europe and migrate to Africa for the northern winter, have been the subject of lyrical folklore in many cultures of South Africa, as well as the nickname for Europeans who spend the cold northern months in southern Africa.

Barn Swallows respond to climate change

Barn Swallows (Hirundo rustica) breeding in Europe have shown well-documented responses to climate change there, mainly by arriving earlier after their African migration, to coincide with the earlier springs that are a feature of climate change. Yet it has not been known what's happening on their non-breeding grounds in Africa, where swallows undergo critical life-cycle events such as moult and refueling after breeding. Do swallows leave their African non-breeding grounds earlier, fly faster, or perhaps not fly as far south as they did previously?

New study shows that Barn Swallows leave SA earlier

The new study in Proceedings uses a novel source of data from two innovative citizen-science projects, the Southern African Bird Atlas Projects 1 (1987-1991) and 2 (2007-present), to show that Barn Swallows certainly do leave earlier from those parts of their South African non-breeding grounds where they used to stay longest. They did not advance their departure, however, from areas in which they stay for shorter periods, which could mean that they are constrained from doing so.

Dr Res Altwegg, population ecologist at the South African National Biodiversity Institute (SANBI) and lead author of the paper, says "Shifts in arrival of migratory birds at their breeding grounds are among the most noticeable effects of climate change, but almost nothing has been known about the phenology (timing of life history events) on non-breeding grounds." By contrast to a wide array of strong studies in the northern hemisphere on climate change impacts on birds and other biodiversity, little has been known until now of how climate change is affecting vulnerable species in Africa.

Other coauthors of the paper include Kristin Broms, a student from the University of Washington, Dr Birgit Erni of the Animal Demography Unit (ADU) and Department of Statistical Sciences at the University of Cape Town (UCT), with which Res Altwegg is also associated, Dr Phoebe Barnard and Dr Guy Midgley of SANBI, and Professor Les Underhill, director of the ADU.

Bird of the Year

The Barn Swallow is the 2011 "Bird of the Year" for the major South African conservation NGO, BirdLife South Africa, which has been promoting this species in a climate change context all year.

Media enquiries

Dr Res Altwegg,

Issued by BirdLife South Africa (BLSA) and the South African National Biodiversity Institute (SANBI)

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Submitted by Lebo Majara at 18/03/2016 - 11:27
Barn swallows generally do not claw onto reeds vertically but sit on branches or leaves which are more horizontal whenever possible.
Submitted by Ingrid Scholtz at 08/01/2016 - 15:05
We are currently visiting Glengarry in KZN and have been watching the swallows returning to their nesting place in the evening. We wonderdered how do they manage to roost on the reeds, do they sit in the leaves or claw onto the reeds whan they sleep. What a beautiful sight in the evening.
Submitted by Joan Lithgow at 15/10/2015 - 16:58
Do barn swallows mate for life? Do they always come back to the same nest?
Submitted by Joan Lithgow at 11/10/2015 - 18:05
Last year at the beginning of November we moved into our new home in Boksburg and found swallows in a nest. They then left just before winter with a baby. My questions are: how long do swallows live for; do they mate for life; are the same swallows coming back again or how do the other swallows know about the nest that is at our home? We have noticed several swallows flying around our property and are wondering when they will find the old nest.
Submitted by Mike Morris at 06/10/2015 - 19:52
I live in Pretoria and have had a swallow nest on my stoop for around 15 years. It seemed to take the birds about 3 years to build. My facination is that every year a pair will use the nest and breed. I am no expert on this lovely bird but find it facinating that every year the birds come back. Does anyone know if this would be part of a family coming back or Is it just random that a breeding pair would find the nest. Thanks in advance. Mike
Submitted by Michael Hickman at 31/07/2015 - 17:38
I live at Mount Moreland where large numbers of swallows roost during their migration to SA. By far the biggest congregation of swallows many times the largest number I have seen at Mount Moreland I have seen at Jwaneng in Botswana.
Submitted by David Rose at 29/06/2015 - 10:54
We had a small group of swallows here in South-West France for one day, 25 June 2015. This must be very late for migration? I have been trying for years to get a photograph of them drinking from a swimming pool and managed it this time with a sequence of four shots. The birds were ignoring flies on the water. The water is lightly salted and very lightly chlorinated.
Submitted by George Gilbey at 25/08/2014 - 4:07
Started watching the barn swallows on our farm in 2013. We have over a hundred nesting swallows in our bank run barn every year They left to migrate on 8/24/2013 and returned on 4/28/2014. What has me amazed is they left again this year on 8/23/2014 almost a year to the day. I will comment next spring when they return.. George Gilbey Beloit Ohio
Submitted by website manager at 20/05/2014 - 14:05
Barn swallows do migrate in loose flocks, although I do not think we generally know whether the individuals in a flock remain together for long during a migration. They certainly congregate at migrant roosts, and fly off together in the mornings.
Submitted by Hugo Knoetze ( at 04/04/2014 - 9:10
I were at Lanseria airport Wednesday last week (2014/03/26) and while waiting for my flight observed many of the Barn swallows in and out of their nests just outside the departure hall doors. Now my question-do certain area located swallows leave on the same time and then regroup somewhere in the air and fly north? Why I am asking-a few years ago I were at Tshipize in the bush veld and observed thousands upon thousands on swallows migrating northwards- I were in the pool and observed them for more than three hours on end?

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