Unless you like confusing fingerings, and/or super limited range I'd avoid the recorder. A tin whistle is a _much_ easier to learn to play instrument, that exchanges chromatic playing (the ability to play in multiple keys), for a much more accessible second octave of range. Go for a brass or nickle round tube one (Generation, Feadog, or Waltons are decent brands).
While we're proposing alternatives to the recorder, I'd add the harmonica as an accessible instrument. It depends on the kind of music one wants to play, but the harmonica is easy enough to start playing for a child, and the range of expressivity has room for expertise to develop (chromatic harmonicas are difficult but can produce sweet and exotic scales..).
