Saguaro Cactus ~Bird Nests...

today was one of those days when you go to a sale and you spend the whole day just making it thru...... and best of all..... one of those CUTEST Grandmas who had tons of her vintage crafting materials and all kinds of wonderful cactus and woodwork materials from her husband's past projects. my mom & i spent hours in the grandpa's workshop & the grandma's sewing room...so much FUN! and i'm afraid i've already decided i need to go back again 2morrow too :p
I know NOTHING about cactus but these are so cool! (& now i have some neat ones :p)... from what i could find her husband made all kinds of cool stuff out of the cactus like frames & buttons.
this picture i'm adding here i was told is a bird's nest that are made in the cactus; they're really cool shapes, hollow some have two "nesty" spots...... would be neat with a little cactus planted inside...anybody know about these? thanks