The mature birds are glossy blue-black, with a pure white underbelly, unlike the dark blue swallows with their peachy-orange throats. The birds can further be told apart by tail shape; the house martin's is a short, stubby 'V' akin to a fishtail, whilst the swallow sports long, slim tail streamers. Both birds spend long hours on the wing, feasting on insects mid-flight.
Between September and October, both swallows and House martins begin to leave Lanhydrock and the rest of the UK to head south for the winter months. It is a hazardous journey of over 200 miles a day towards destinations in Africa, Arabia and the Indian sub-continent. Next year, they will return to the same nesting sites to raise the next generation of Lanhydrock fledglings.