The saguaro is abundant in the Sonoran Desert. It has many uses, including furniture making. It is also home to many of the desert's fauna.
Here are two photos of bird nests in one Saguaro I found while hiking on Silly Mountain, near Apache Junction Arizona.
These next photos are of a different Saguaro, same hike, same mountain.
Lets peak a little closer, a feather, and behind it, a nest?
I found this as I was taking a photo of this little guy, same saguaro.
And, a little bit closer:
Believe this is a cactus wren. Sony was zoomed almost to the max, bird still a little out of focus.