Wow..... you got more adventurous in editing, Edu..... very watchable short gem because of the brisk pace, great choice of music as well!
The opening title scene looks great, but I think you should reserve it to a piece longer than 30 sec to leave more time for the bird clips. Great job in pulling it off though and this clip gave you good practice on such.
Personally, I'm not too keen on fancy transitions for nature films..... I only use cross-dissolves, plain cuts and dips to black.