Coronado NF
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  • Bear Canyon Tour

    Saguaro Condo

    Purple Martins Nesting in Large Saguaro.

    The Saguaro cactus is the signature plant of the Sonoran Desert. It is a succulent that expands like an accordion as it stores water from rainfall. A Saguaro that is full of water can survive for about 2 years without any rainfall. The long spines allow raindrops to drip off the ends, slowing runoff. Its shallow roots extend outwards as far as the plant is tall, so they are able to take up water as it runs off during rain. There is a shallow taproot that extends down about 6 feet. The Saguaro is said to get its first flower when it is 60 years old and its first arm when it is 75, but these numbers are quite variable. Some Saguaros never get arms. The bright red fruit is very tasty and may be fermented by the Tohono O’Odham Indians to make wine.  A Saguaro can live about 150 – 200 years.

    The many small, round holes in this Saguaro were created by Gila Woodpeckers and Flickers to serve as nests for their young.

    The Purple Martins, the largest of the swallows, shown in the photo outside the nest are a male and a juvenile.

    The next photo shows the female with her head sticking out. These birds have returned to this nest (the top hole in the tallest trunk) for four years, starting in 2015.They are common in Pima County in the desert from mid-May through September. 

    Another resident observed in this “condo” was an Elf Owl. The photo was taken around 8:30 am in June.

    The linings of the nests are woody structures created by the Saguaro in response to the “injury” by the woodpecker as it makes the hole. These nests are often found inside the woody remains of dead Saguaros and are referred to as Saguaro Boots due to their shape. Woodpeckers generally abandon their nests after one season and other birds may take up residence.

    Continue along the Bear Canyon path to the intersection with the paved Bear Canyon Road. There is a large rock in the center of the trail at this intersection. Turn right and continue along the paved road.  Most of the vegetation that you will see along this part of the walk is called Sonoran Desert Scrub. Besides the cacti and Ocotillo, you will see the Foothills Palo Verde and Velvet Mesquite and Acacia trees, many in bloom depending on the time of year and the amount of rainfall. What do you notice about the leaves on these trees? The small leaves reduce water loss while still allowing photosynthesis to take place. 

    You will eventually reach an intersection with the road that crosses the Bear Bridge on the right. There is a restroom at this intersection. If you turn right and cross the Bear Bridge, the Bear Canyon Road continues and eventually reaches the 7-Falls trailhead. If you wish, you can walk down to the bridge and then return to the paved road. 

    For this tour, we will continue straight on the paved road. You can now begin to see Sabino Creek and the well-developed  riparian zone beside it. The creek gives life to the riparian and desert flora and fauna within the canyon. This creek depends on rain and snow melt from the huge watershed in the Santa Catalina Mountains.  Continue until you see the large “Gneiss” gray and white rock on your left. This is an example of one of the most common rocks found in Sabino Canyon. It is “Catalina Gneiss”, pronounced “nice”. It is a banded gray and white metamorphic rock and usually can be identified by its layers. Five main minerals make up a “gneiss” rock: feldspar, quartz, mica, magnetite and garnet. Look for other samples of this rock as you continue your tour. These Santa Catallina Mountains were formed over 12 million years ago. 

    Just North of the Gneiss rock you will arrive at the “traffic circle”. Private vehicles have not been allowed in Sabino Canyon since 1978. However, the Sabino Canyon Volunteer Naturalists are allowed to lead a busload of school children into this area for their environmental education program. They bring about 7,000 children every year to the Canyon. 

    The picnic tables and restrooms give visitors a place to rest, fill up their water bottles and enjoy the sounds of the creek.

    To the East on the South side of the restrooms are steps leading down to the creek which is where you want to go now.