J. Stuart Rowley writes to me: "I found that the weekend nearest the 15th of April was the ideal time to hunt nests of this warbler on Catalina Island, and after much hiking about this island I finally located a little ravine, only about a mile or so out of the town of Avalon, where these warblers nested abundantly, due to the little trickle of surface water in the bottom of the ravine. Since most of the ravines here are dry, this one was 'made to order' and I enjoyed the chance to find many nests in the short time allotted to me. Around the middle of April this little ravine fairly trilled with the songs of many males, who were constantly pursuing trespassing individuals out of their nesting territories, only to return and continue their melodic songs." _Nesting._--Of its nesting habits, J. Stuart Rowley continues: "I have found dusky warblers nesting in every conceivable sort of place, ranging from those placed on the ground in the grass to those placed 15 feet up in toyon trees. The usual nesting site here seems to be in a small toyon bush, rather well concealed, but not over 2 to 3 feet from the ground; the nests are made of fibres and grasses and, although nicely cupped and lined, are rather bulky affairs externally for a warbler to build." Howell (1917) writes: The usual nesting site of the Lutescent Warbler is on the ground, but I have never heard of _sordida_ building in such a situation. On the smaller barren islands, such as the Coronados and Todos Santos (where it is common), they build in a bush or tangle of vines, a foot or so above the ground, and the nest is always mainly constructed of gray moss, where this is to be had, lined with a little fine grass. On the larger islands, where there are good-sized trees, the site chosen may be a thicket of vines several feet above the bed of a stream, a small shrub, say four feet up, or perhaps an oak as much as fifteen feet above the ground. In such case the nest is quite substantially made of leaves, twigs, bark, rootlets, and often a little sheep wool. Three or four eggs constitute a set, and at least two broods of young are raised each year. A most unusual nesting site for a dusky warbler is described by Clinton G. Abbott (1926). It was--