Nest Pocket Sea Grass w/roof. This nesting bag has been designed for the wren. The best place to hang the nesting bag is a quiet and somewhat sheltered spot, therefore not in the direct sunlight or on the side catching the rain, and an obstacle-free approach route for the bird. Fall is the best season to clean out the nesting bag. Many times during winter the nesting bag offers protection to birds seeking shelter in severe weather conditions.