The Pavarotti of the avian world, this 4 ½ inch tiny singer will let go day or night and any day of the year with a repertoire of 25-40 or more songs. A bold and beautiful trilling, energetic and flutelike melody sometimes interpreted as teakettle, teakettle, teakettle, he is competitive in song as well as nesting territory. Usually monogamous, the pair has been known to nest in boots, buckets, coat pockets and mailboxes. But they can be killers when they invade other nests.