This might be another long shot. I found this structure in the lid of a compost bin, it has been there all winter and is still there now (June). It looks like a nest for a spider cocoon, with the silk threads holding it in place. It appears to be smeared with earth, bits of vegetation and the exoskeletons of dead animals. Does anyone know what type of spider (or other animal) makes structures like these? I am very curious to learn what it could be. Thanks