Actually, it's a rather complicated story. The bird was lost and made its way to the army camp. One of the recruits was wearing green feathers in his hair," replied Elrohir.
"Green feathers! Someone needs a lot of advice on fashion sense," muttered the Lady. The thought of anyone wearing green feathers in their hair was disturbing to Arwen; but one of the army recruits doing so was enough to make the Evening Star mildly ill.
"Well, the parrot thought the Elf was a female bird and became attached to him instantly. Aragorn actually had to kiss the recruit to get your pet jealous just to get him off the new recruits head," finished Elladan.