On July 6, 1959, I found a nest of the Yellow-bellied Flycatcher(Emipidonax flaviventris) with four young in Reese’s Bog, a few miles south of the University of Michigan Biological Station, Cheboygan County. This is the first positive record of the species breeding in lower Michigan. In 1957 I had seen the Yellow-bellied Flycatcher and heard its territorial calls in June and July while working through Reese’s Bog (Pettingill, 1958, Jack-Pine Warbler, 36: 9). Again, in 1959, beginning in June, I observed the species in the same area. Finally, on July 6, near the north edge of the Bog, I came upon a pair which showed alarm at my presence. Retiring some distance to sit quietly and watch, I soon noted one bird and then the other drop to the ground with food, thus revealing the nest site. The nest itself was several inches under a big root from a mossy stump and its entranceway was concealed by a low branch of a small fir-balsam. A few widely separated spruces and aspens in the immediate vicinity provided moderate shade. The sun was shining on the fir-balsam at the entranceway when I discovered the nest. Materials used in the construction of the nest comprised strips of bark and pieces of dried moss compacted together for the bottom and sides, slender, yellowish grass stems, dark rootlets, and very fine unidentifiable plant fibers for the lining. Bits of fresh green moss lay over the rim and side facing the entranceway, making the nest blend with its surroundings. On the day I found the nest the four young were about ready to leave. They were, in fact, so well developed that they filled the nest cup and extended over the nest’s rim. Only one young bird was in the nest when I visited it the following day, July 7.