Common House Martins or Barn Swallows? I think they are Barn Swallows because of the rusty-orange throat and forehead and a pale orange chest and underside. Besides, they are the most widespread swallow in found in Europe, Asia, Africa and North and South America.
They fly around all day looking for insects to eat, then go to slumber upon this cable every night, top to tail, or beak to tail! Their old nest is nearby, where they might return to after their winter migration, if they survive and make it back okay.
They'll be off soon, come September/October, heading south for the Winter to hotter climates, wintering in South Africa (wish I could join them, the journey there taking them about 6 weeks to complete. Swallows was/is a popular tattoo with sailors, a symbol of long journeys and it became a symbol of a safe return. Even though small, they are swift, flying from 200 up to 600 miles a day to reach a destination, around 6,000 miles in total. They only live 4 or so years though, at most up to 8 or 10 years, but this is rare.
They used to come every Summer (apparently from Africa) to ours sheds and have their babies high up in the rafters. My father always looked out for their advent and when they arrived he said they heralded the beginning of Summer. I remember how funny it was the way they used to dive-bomb the cats when they were crossing the yard. Yes, they will bomb-dive anything or anyone who they deem as a threat to their babies. They're so small, yet courageous! They migrate, each year, but some do not make it, dying from starvation and other things along the way, but yet they go. Migration is fascinating really, and the animals who do it.
They'll be back again come April of next year and I hope to see them then again.