How to make a swallow nest

Swallows can build their own nests. They mainly use twigs and mud, and make nests with their own saliva. They are all tightly attached, so a small hole is left in and out. If you want to help the swallow build a nest, you'd better prepare a big roof for the swallow. Swallows like to nest on the eaves. You can also make a bird's nest with holes in a wooden house, but swallows may not be able to get in. Because swallows are very diligent and like to make their own nests, but once swallows nest in your place, they must not destroy it, otherwise they will not come next year.