Traditionally people associated the song of travelling birds, especially in spring with withering and ill luck. (Birds visited the lands of the dead during the winter). To prevent it, people had to have at least a tiny morsel of food before going outside, to cheat the birdsong out of its power and ensure your own presence in "this world" with food. This was called "linnupete". The word is also used for a small meal or a snack nowadays. The actual tradition to have it mostly disappeared over the end of 20 century with older generation. Probably Latvians and Finns also have a word for this custom.