"Alouette" is a popular French-Canadian children's song about plucking the feathers from a lark, in retribution for being woken up by its song. Although it is in French, it is well-known among speakers of other languages; in this respect it is similar to "Frère Jacques". Many American doughboys and other Allied soldiers learned the song while serving in France during World War I and took it home with them, passing it on to their children and grandchildren.
Its origin is uncertain, though the most popular theory is that it is French-Canadian. The song was first published in A Pocket Song Book for the Use of Students and Graduates of McGill College (Montreal, 1879). However, Canadian folklorist Marius Barbeau was of the opinion that the song's ultimate origin was France.
Looking back...funnily, in Mallu, we always use to sing this as "Kaalu Vetta, Gentle Ayittu Vettu".... which has a totally different meaning !!...
More details about the song can be found at : https://en.wikipedia.org/wiki/Alouette_(song)