_Voice._--Mr. Dawson (1923) says: "The Lucy Warbler is a loud and industrious singer, but the song has a curious generic quality very difficult to describe. It is _Warbler_ song, rather than the song of the Lucy Warbler. It is, perhaps, most like that of the Pileolated Warbler (_Wilsonia pileolata_) in quality. After that, it reminds one of the Yellow Warbler's song, having the same vivacious cadence, but not being so sharply piercing. Again its breathless, haphazard quality suggests one of the Buntings; and I once followed its tantalizing seductions for half an hour under the delusion that I was on the track of the coveted Beautiful Bunting (_Passerina versicolor pulchra_)." Dr. Grinnell (1914) says that the song "resembles the song of the Sonora yellow warbler in length and frequency of utterance and somewhat in quality, but with a distinct hurried and lisping effect reminding one of the song of the Lazuli bunting." Several others have noted the resemblance to the song of the yellow warbler. Mrs. Florence Merriam Bailey (1923) puts the song in syllables as follows: "_whee-tee, whee-tee, whee-tee, whee-tee, whee-tee, whee-tee, whee-tee, whee-tee, whee-tee, wheet_, and its call was a faint _chip_." _Field marks._--There are no very striking marks on Lucy's warbler; it is clothed in quiet colors and in general appearance suggests a warbling vireo. The chestnut crown patch of the male can be seen under favorable conditions, but on the female it is seldom in evidence. The chestnut upper tail coverts can be seen only when the bird is in certain positions. Its activity will mark it as a wood warbler, and it is the only one of this family likely to be found on its breeding grounds among the mesquites in the nesting season. _Enemies._--Mr. Howard (1899) says that "many nests are destroyed by wood-rats and snakes." And Mr. Dawson (1923) writes: Dwarf Cowbirds are prominent in the formidable host of enemies which this tiny bird must face. Sometimes the warblers are able to entrench themselves behind apertures so narrow that the Cowbird cannot get in; and once we saw the Cowbird's foundling resting unharmed, but also harmless, upon the "doorstep," not less than two inches distant from the warbler's eggs. Another nest, more exposed, contained three eggs of the arch enemy, and had been deserted by the troubled owners. The Gila Woodpecker is an especially persistent enemy. Accustomed as he is to poking and prying, he seems to take a fiendish delight in discovering and devouring as many Lucy Warblers' eggs as possible. We caught several of these villains red-handed, and we found reason to believe that more than half of the nests in a certain section had been wrecked by them. Add to these the depredations of lizards, snakes, and, possibly, rats, and the wonder is that these tiny gray waifs are able to reproduce at all. DISTRIBUTION _Range._--Southwestern United States to central Mexico.