September sees 80% of swallows leaving the country to make the dangerous journey back to South Africa. Many of the birds we see over our houses during this month will be young birds migrating for the first time. A number of organisations have been putting little transmitters on our swallows to see where they travel on migration; how far they go and the threats they face on migration.
Swallows weigh less than three tablespoons of sugar and their brain is only slightly larger than the size of a pea. The adults will generally begin their migratory journey first; normally the adult male, leaving the female to do most of the work in feeding the hungry juveniles. Male swallows are quite lazy and having mated and helped a little with nest building often leave the females to do the lion’s share of rearing the young birds.
Typically a nest will contain three chicks. One of which is quite likely to die before fledging (developing wing feathers that are large enough for flight) and two will probably survive. Birds conceived in mid-spring will be in the air during August and September and most will leave for warmer places before the big autumn storms arrive.
Once the birds are ready to fly, the female will coax them out with offers of food and eventually the youngsters will brave their first flight – often only making it a few metres before needing to land. A swallow flying for the first time can be an incredibly moving sight, especially when one considers that it will have a 10,000km journey ahead of it. As soon as the female is confident of the youngsters fending for themselves, she too will migrate, leaving the young birds behind. It will be the last time the fledglings will ever see their parents.
The fledged birds will learn to fly and feed for a week or two in the UK before they begin a gruelling journey from the UK through France and Spain, crossing the Mediterranean at its narrowest point, at Gibraltar; and then flying along the Algerian and Morocco coasts. This first 2,000km is fraught with danger from hunters with guns, who target swallows in southern France and again in north Africa. Not all young swallows will get as far as Africa, maybe 1 in 6 will be killed before leaving Europe.
Swallows then have the challenge of another 2,000km – but this time across desert. The Sahara can be one of the most dangerous places for migrant birds with extreme heat, no water and sudden high winds. Another 1 in 5 birds may perish over the desert and become food for birds of prey.
In the following two weeks young swallows – if they have made it this far – will cross the Equator and head south through Angola, to Namibia and eventually to South Africa. Most swallows will end up spending the winter period in one huge reed bed near Durban in Kwazulu Natal. They will arrive and spend the period from November to February within 5km of their parents and yet will never see them. Scientists still struggle to understand how it is possible for a swallow, that has never made the journey before, to know that it needs to travel all the way to South Africa to one particular reed bed a couple of minutes flight from its parents.
And then in February, swallows will start their return journey to the UK. In a typical year one swallow will travel over 20,000km and in a bad year just one in three birds will make the round trip.
So stop. Look out for swallows and give them a clap as they leave their nests and make their way south. And next year make every opportunity to provide these incredible birds with a place to nest and breed when they return. With climate change, hunting and drought, the future for swallows is very uncertain. But we can provide nest sites and wildflower areas for them to feed over. Let’s do our bit and help our incredible swallows!
This blog was written by A Rocha UK’s Head of Conservation, Andy Lester for the Wild Christian email, ‘Nature and Praise.’