My interpretation, besides the part of the birds and their nest, is: someone’s leaving, (maybe to another country or something like that) but this obviously doesn’t mean bonds are gonna get broke, you can wait for them. Prepare yourself as home and be ready to receive them with open arms and all the things that made YOU warm. <3
Plus: this is such a cute and lovely song that makes me feel comfortable, warm and at home so I listen to it to sleep. :)