Dr. Merrill (1878) says of its haunts: "Arrives about the third week in March, and passes the summer among thick woods and near the edges of lagoons where there is Spanish moss." We found Sennett's warbler fairly common around Brownsville, especially on the edges of the resacas, partially dry old river beds where the trees, mostly small mesquites, are more or less draped with _Usnea_ and suggest the places where we would look for parula warblers in the north. In appearance and behavior they were strikingly reminiscent of our northern friends. Sutton and Pettingill (1942) found this warbler up to 2,000 feet elevation in southwestern Tamaulipas, in full song on March 14, and a pair copulating on March 20. _Nesting._--Dr. Merrill sent to Mr. Sennett (1878) the following description of a nest he found near Brownsville after Mr. Sennett left: "My nest of _Parula_ was taken July 5th, about five miles from here. It was placed in a small thin bunch of hanging moss, about ten feet from the ground, in a thicket; was simply hollowed out of the moss, of which it was entirely composed, with the exception of three or four horsehairs; entrance on side; contained three young about half fledged. Parents very bold, but thinking they were _americana_ I did not shoot them." The next year, his Mexican guide brought him a nest and a broken egg, which Mr. Sennett (1879) describes as follows: The nest is exceedingly interesting and beautiful. It is made in a gray mistletoe-like orchid, an air-plant very common on the Rio Grande, which establishes itself on the small branches of trees, and varies in size up to eight or ten inches in diameter. This one is six inches long by four and one-half inches wide, quite firm in texture, and was fastened some ten feet from the ground, to the end of a drooping branch of a brazil-tree in open woodland. The nest is constructed very simply, being formed by parting the gray leaves of the orchid and digging into its centre from the side, a cavity some two inches in diameter being made, with an opening of one and one-quarter inches. The bottom and sides are lined pretty well up with short cotton wood fibres, forming a fine matting for the eggs to rest upon. A firmer and more secure nest is seldom seen, although so easily made. I imagine a day would complete one, and certainly but little time need be wasted in selecting a site, for thousands of orchids stand out on the partially dead branches on trees with little foliage. That they build also in the hanging trusses of Spanish moss, so abundant everywhere, is true, the young before referred to being found in a nest in one.