Hello, I've just discovered this forum and am hoping to learn more about the birds here in south west France. The one that brought me here today is a complete mystery to me. We have a lot of house martins every year, behaving as house martins do. But this year there seems to be a different bird living with them. It is about the same size or maybe a little bit smaller, brown all over I think (although it's difficult to get a close look). It perches on the roof and makes a loud clicking sound when I or the dogs are outside near the house martin nesting area. I'm wondering if the clicking could be an alarm or warning sound. When not perching on the roof, it seems to be joining in with the house martins as they are flying. Any ideas what it can be?