Quoting Luca: “Our lives are complete”. Yellowstone (26 June)

In order to be out and about before the animals, some of our group rose early, some as early as 3.00 am. We weren’t among them but we were on the road by 6.10 am. Merryn wishes all readers to know that she was dressed and sitting in the navigators seat.

We were rewarded when we came upon a group of other animal spotters. They had found a grizzly bear and her cub. We spent about 20 minutes watching while illegally parked (motorhomes don’t pull off the road quite as easily as cars). The bear was a bit shy, keeping herself partly secluded behind a tree and we couldn’t get any useful photos of her. She moved about a bit and that was thrilling enough but then we realised that she was supervising her cub playing because the cub moved out onto a log and rolled about before mum called it back and before we could get cameras going.

We continued our drive and passed several bison, both solitary and in small groups. We thought bison were old hat by now so kept driving but stopped when we came over a hill and saw a valley spread out in front of us and covered in bison. They were everywhere in their various groupings. About half were sitting or lying down while the others were feeding. The calves were straying small distances from their mums and playing with other calves. 

The picture below shows only a small section. This valley of bison was probably 1 km across and 4 or 5 km long and the bison were scattered all over it. At a rough estimate we think there were over 1,000. We have seen bison all over Yellowstone so this represents a remarkable recovery from the lowest count of 24 from whom all of these have descended.

Another thrill was finding a “soda butte”. As we looked at it we encountered a young couple who encouraged us to go around the other side and see some bird nests. The birds were swifts and they had build their nests from little pellets of mud, each about the size of a pea. They collected the mud from a wet area adjacent to the nests and then formed the nests beneath an overhang of the butte and stuck to the side. We could see little heads poking out and parent birds flying to the nests, possibly feeding them, although we didn't see closely enough to be sure.

We continued to see deer, including a mule deer, and some goats. However, we were now headed for geology and began with the petrified tree. Yellowstone doesn’t have a petrified forest but it has a petrified tree. There used to be three of them but two were souvenired and vandalised before protection of such things was considered important. It’s a redwood which was caught up in a volcanic event about 50 million years ago. The information at the site said that it was engulfed by the lava and a process of cell replacement began fairly quickly which is different from the process in Curio Bay where the lava-trapped trees were flooded with seawater and over time the minerals in the sea replaced the organic cells of the tree.

We moved on to Yellowstone’s Grand Canyon. It’s perhaps not as grand as the one in Arizona but it is spectacular. It varies from 250 to 350 meters in depth and from 450 to 1,200 meters wide. It’s almost 40 km long. The predominant colour is yellow and leaves us wondering if this is connected to the name Yellowstone. The formation of the canyon began about 50 million years ago when the same eruptions that created the petrified tree began and continued for about 10 million years. Things quietened down and the usual forces of wind, water and ice eroded the rocks before a tremendous volcanic eruption about 1.5 million years ago. Lava from this eruption followed the course of the eroded river and was rapidly cooled resulting in vertical columns that look like a picket fence. (Check the photos.) Since then there have been more glaciers and erosion and the process continues.

We have seen evidence of fires throughout Yellowstone. Typically we see an area of dead trees, partly blackened but also bleached by weather. Some remain standing while others are scattered about on the ground. The ground is covered with new, naturally regenerated trees. In the old days, park personnel used to put fires out whenever they could. They eventually concluded that they were interfering with a natural process and this prevented regeneration while also allowing dry matter to accumulate and feed fires. Now they only intervene when people or animals are endangered.