The Barn Swallow at rest!

When the Swallow is at rest on a cable like this.You realize just how small and delicate they are? So how on earth does it fly to Africa and back, each year and find their nest site again.
A Farmer friend of mine, says,he has seen Swallows using the same site in a barn on what was his Father's farm,for over 8 years.Surely these nest sites are inherited from generation to generation.That makes it even more amazing!!!!