Wednesday, February 04, 2015

Please Stay on the Trails When You Hike

With another perfect day in the offing we headed once again for an 8:30 morning walk at Tucson Arizona's Sabino Canyon. The route took us on an approximately three mile loop up the Esperero Train to the Bluff Trail, then to Sabino Dam, and finally back to the visitor center. 

Our most important nature lesson of the walk had to do with these strange little pictures of dirt.






This deposit of blackish crust on the desert floor is a living growing substance called cryptogamic or biotic desert soil.  It is what holds the desert floor together and can take 30 to 50 years or more to grow and form. One careless hiker stomping through it can erase many years of patient development in seconds. If you want to know more about this critical element of sparsely vegetated ecosystems you could look at this site http://science-ed.pnnl.gov/pals/resource/cards/cryptogamic_crust.stm  Our naturalists all tied this type of soil to the importance of staying on the trails so as to not interfere any more than you have to with the natural surface. This was new to us and for the rest of the hike we were all looking for patches of this important desert material. And of course we exercised renewed caution in where we were stepping.

Some of our other morning highlights

Ann, our main guide, brought us a bag full of barrel cactus fruits from a plant in her own yard  to taste. In nature they look like this.



She had cleaned them up nicely and here one of our group prepares to take a bite. I had a taste too and found them rather sour but not completely unpleasant. 

Bird sightings are always a part of these walks. Today we saw a nice Gila Woodpecker on the top of a Saguaro.

 
And a nice Anna's Hummingbird on the top of a branch.

 
It continues to look like an early spring and more and more desert plants are showing signs of buds and blooms.  Yesterday we only saw single bloom on a Globe Mallow. Today we ran into a whole bush full of blooms.  Lots of little butterflies were swarming around it as well.

 

 
This bright little thistle looks almost like a dandelion. I don't know its true name.
 
This is a plant called Filagree and it has tiny delicate little purplish pink flowers.

 


After negotiating the Bluff Trail we ended up once again at Sabino Lake.  The dam that created the lake was built by the CCC in the 30's,  but sedimentation over the years has turned it pretty much into a small pond that is still pretty, but clearly no lake.

 
I caught this young fellow checking out the depth along the shore. 


Down below the dam the recent rains are continuing to feed a lot of water into the lower part of the creek.
 

 
Some features of the streambed go back much further than the Great Depression era. Below you can see a depression used as a metate by ancient dwellers for grinding seeds or grains as they camped on the shore.
 
 

Our luckiest sighting of the morning was a white tailed deer resting peacefully on the hillside and staring right at us.  Our guide noted that the deer do like to come down into these areas because they know that the presence of people also keeps the deer's main predator, the mountain lion, away.
That knowledge was tied to the fact that hummingbirds like to build nests near hawk's nests because the hawks have no interest in hummingbirds, but they do keep the area around their nests free from snakes and other predators who find hummingbird eggs attractive. 
 
 
That's it for today.

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