Swallows are summer visitors to the UK. They start to arrive here from Africa in April. By early June most swallows have started breeding and by July, the first brood of young has usually left the nest and flown away. The parents will normally then go on to raise a second brood, sometimes even a third.
Click here to read the rest of the article.: Swallow Migration | When Do Swallows Migrate? – The RSPB