The question hadn’t occurred to me until I stood there watching molten rock from the volcano Kilauea, in Hawaii, flowing into the ocean. Lava, on occasion, explodes when it’s rapidly cooled by sea water sending tracers flying. But what makes magma (molten rock below the earth’s crust) flow out of shield volcanoes like Kilauea in spattering bursts and fluid rivers of lava (molten rock on the earth’s surface) while strato-volcanoes like Mt. St. Helens explode with such tremendous force?
In a word, the answer comes down to viscosity. As nature would have it, what makes magma fluid or thick and “gooey” comes down to a fairly complex cocktail including the chemical composition of the source rock, temperature and gas content. In Brief, low viscosity magmas flow more easily and allow gases to escape and the thick stuff can trap gases building pressure to the point that literally moves mountains. In either case, when magma reaches the earth’s surface it’s an awesome sight to behold.
Shortly after my observations at Kilauea I became aware of the Soufrierre Hills volcano that was devastating the carribean island Montserrat. I couldn’t resist the opportunity to witness an active shield and strato volcano within six months of each other.
In Hawaii the relatively fluid lava has been blanketing the slopes of Kilauea and adding land mass to the big island for centuries. People have been displaced from their homes and a new Park Service Visitor’s Center was leveled shortly after its completion. On Montserrat the capitol city of Plymouth was devastated by volcanic ash and the airport rendered nonexistent by a pyroclastic flow. Refugees crowded onto a corner of the island shielded by topography from the volcano’s wrath. The island felt very small indeed when a small eruptive event sent an ash plume 15,000 into the sky during my visit. What a difference a bit of viscosity can make!
The smell of rotting fish tends to grab your attention… so does fresh bear poop. I also notice, in some places, the thick vegetation along the stream I’m exploring in Western Alaska lies flat where a bear had been sitting. The spruce forest closes in behind me as I round several bends and my senses are on alert. I’m looking for a place to photograph sockeye salmon on the final leg of their life cycle.
The sockeye began here as fry hiding among the wood debris, careful to avoid the trout. As fingerlings, they left the confines of this small stream venturing, on impulse, into the lake and then downriver to Bristol Bay. In the salt water they made their living, growing several fold in the rich marine environment. Many would fall victim to hungry predators along the way. But these salmon made it back carrying the stuff to spawn a new generation and ready to leave nutrients from their decaying bodies in their natal stream. Microscopic organisms on up to large coastal grizzlies benefit from this rich food source cycling inland from the sea.
The salmon scatter as I slide into the cold, clear water. Soon they will be back, driven by their need to continue up stream. While I wait, I think about how bears wait for the salmon to return too in this place where people seldom visit. Their ability to survive a long cold winter may very well depend on their success catching these fish.
For a moment, I wonder what a bear might think if he peaks over the bank and sees me laying motionless in the water in my black wetsuit. Will I look like a smaller bear fishing in his spot? Then I glance downstream and a beautiful red sockeye is just a couple feet from my head and my thoughts are filled with a sense of wonder and admiration.
I’ve come a long way to be here with these salmon. As I contemplate their amazing journey to the ocean and back to this tiny stream of their birth, my trek seems like nothing at all.
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A great thing about bird watching is you can do it just about anywhere you go.
It’s their diverse survival strategies and highly mobile nature that make birds so successful at exploiting almost every habitat niche this world has to offer. Understanding these traits and a few specifics about the avian species in your area will help you succeed in making the ultimate bird watching habitat in your own yard.
Simply adding a feeder will likely produce some activity, but you may soon notice that some birds only eat the seeds spilled on the ground around the feeding station. Different birds employ different feeding strategies. While some flit around the canopy of trees looking for their next meal others are down in the under brush trying to find a snack. By varying the height and locations of your feeders you’ll provide for a more diverse group of avian visitors to your garden.
Birds need security from predators too, so consider placing high feeders near vegetation that can provide cover in the event of an aerial attack and put ground feeders far enough away from cover that might conceal a cat.
A water feature of some kind will complete your bird buffet. A shallow tray, custom bird bath or pond in your landscape will all do the trick. Even in moist environments, birds love to have a pool for drinking and bathing. Keeping their feathers clean and healthy is essential to their survival.
The many birds frequenting my yard provide endless opportunities for enjoying my bird watching hobby while I work around the house. And the songs the birds bring to my garden give an extra special quality that only nature can provide.
Birds seen out the window while writing this post: dark-eyed juncos (30), varied thrush, song sparrow, black-capped chickadee, spotted towhee, mourning dove, steller’s jay.
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varied thrush