Prevue Pet Products BPV103 Cotton Thread Fibers Bird Nesting Material Box Go to amazon.com Related posts bird house nesting materials buyer's guide for 2024 FeatureContains natural cotton fibersAttaches easily to cagePerforated pop-out opening DescriptionPrevue's nesting material box has everything your bird needs to nest. It easily attaches to any cage so birds can have quick & easy access to the fibers.