Originally, the Barn Swallow nested primarily in caves, but gradually they converted to breeding under the eaves of buildings or inside artificial structures such as bridges and even deserted pipes.

• 最初，家燕主要筑巢于洞穴里，但是逐渐地，它们转变为在屋檐下或人造建筑物里，例如大桥，甚至在被废弃的管道里扎巢。