Found in southwestern desert and mountain areas, yucca stalks grow to sixteen feet.  Once harvested, the trunk of the yucca can be used for a variety of purposes.  This particular line of bird toys was developed because the outside of the yucca (its skin) is tremendously durable while the inside of the yucca is nice and soft.  You will find that parakeets and budgies will hollow out the entire log and nest inside the skin.  Small and medium sized parrots love to shred the softer inside portion of the yucca and large parrots will simply destroy it ? inside and out.