On a recent hike in Arizonas Sonoran Desert, I stumbled upon one of natures most remarkable dwellings. It wasnt made by force of water, wind or sun. And it wasnt made by any creature either well, not quite. Im talking about the Saguaro Boot. What in the world is the saguaro boot and what makes it the deserts most versatile dwelling? The saguaro boot has an interesting story, one worth telling, and here it is.

The beautiful Gila Woodpecker (Melanerpes uropygialis) is native to the Sonoran desert and can be found anywhere the giant saguaro cacti are found. It builds its home in the saguaro cactus by drilling a hole in the side of the cactus and excavating a cavity for itself and its offspring. This cavity is usually a foot deep! When the woodpecker vacates this new home in approximately one year, other birds will then use it as their own.

Heres the interesting part. In order to prevent water loss due to this new hole in its side, the cactus will form a callus over its exposed surfaces. This callus will remain inside the cactus as long as it lives and will act as a permanent waterproofing seal. This scab will also protect the cactus from other maladies caused by infection.

Once the saguaro cactus has lived out its life, and this can take 250 years, it will decay and disintegrate as all living matter does and it will leave behind this callus that once protected it. Because the Gila Woodpeckers home started as a hole in the cactus and widened into a larger cavity, the callus when separated from the saguaro cactus looks very much like a boot. The boot, while caused by the woodpecker, is actually grown by the cactus as a defense mechanism.

Over its life time, the Gila Woodpeckers home in the saguaro cactus will be the primary residence for dozens or even hundreds of birds such as the Cactus Wren, Kestrel or Elf Owl and when the cactus is gone, the boot will offer shelter to a variety of other wildlife such as mice, lizards, snakes, spiders and insects.

The next time you see a hole in the side of a saguaro cactus, think about all of the residents who will use the Gila Woodpeckers nest as their home. Take a friend on a hike and look for the illusive saguaro boot. Nature is wondrous and its flora and fauna are remarkable. Get Outdoors!