I was quite lonely when I first moved to Kumamoto, knowing nobody and not speaking the language, but the call of the mourning dove (a plaintive cooOOoo-woo-woo-woooo) comforted me as it recalled my California youth.
“Hato” (鳩) refers to both pigeons and doves, but the mourning dove is often referred to as “yabato” (野鳩, or “wild pigeon”), which is interesting as they appear to have originally been brought to Japan from their native North America as pets. They are more slender than the pigeon and sport a tan plumage. They mate for life, so if you see one, look around and you’ll see the other (they never flock). Delightfully, their chicks (always two) are known as “squabs.” Two pairs are nesting at my house in trees front and rear, and now, as they raise their squabs, their calls to each other brighten the morning. You can read more about them at the below Wikipedia link. - William