Snapedom

It really ought to have hit me sooner, in light of a certain fairy tale by one Hans Christian Andersen (at least, things ought to have ended up as they do in the fable...JKR did a number on the poor fellow). So, quiz time. I'll give you a hint: it's a bird (he does have a rather impressive beak, one must admit). :)

What bird...

... is often a symbol of love or fidelity because of its long-lasting monogamous relationships (should one die, the other will usually live out the remainder of its life alone) [need I say more? this is canon-Sev we are talking about]
...is revered in Hinduism and compared to saintly persons whose chief characteristic is to be in the world without getting attached to it, just as a ___'s feather does not get wet although it is in water [he doesn't seem particularly...attached to much, does he?]
...has a name derived from the same root as the Latin 'sonus' (sound) [that famous voice]
...is known for its coloration and sometimes "aggressive behaviour towards students" (there are five of these birds at the University of York)

Click for a photo of Sev transformed.