For those planning to try for the Black-throated Gray Warbler in Grand Rapids, here are some helpful specifics. Park behind the building and walk atop the berm overlooking the Grand River. There are two feeders, both placed above the railroad tracks at eye level, one each at the northwest and southwest corners of the parking lot (in green on the map). The bird spends the majority of its time associating loosely with a chickadee flock which is usually (but not always) near or south of the south feeder. Starting at the south feeder, walk south on the railroad tracks while scanning out toward the river- the bird is often in the branches overhanging the open water. Occasionally the bird makes forays toward the building, foraging mid to high in the canopy of the Red Pines flanking the building. So far I've seen it once in a pine at the west entrance and at least four times in one at the east entrance (this is where I discovered the bird initially as well).
All morning long on 28 Jan the bird was present along the river (between 10AM and 12:30PM), but interestingly in the afternoon (2-4PM), almost all of the sightings were in the pines adjacent to the building, especially the northeast tree.
If you come, please consider bringing some mealworms or peanut hearts, and putting them on the platform feeder. With any luck, this bird may stick around all winter.