More of Genovesa: Lava Cactus, Swallowtail Gulls, Marine Iguanas

Before moving to a new home disrrupted my life, I was writing about the return to Genovesa Island in the Galapagos.  We begin the second visit with a walk past tidal lagoons, meeting herons and frigate birds like those we saw earlier today.
As we turn to head back to the landing spot on the beach, I'm once again gaping at this strange world around me  Now it's the lava cactus strike me.

Lava Cactus

This plant, one of the first to grow in an inhospitable sea-level lava field, has short stems and grows in clumps that can expand up to six feet.  While it is unique to the Galapagos, certain cactus facts are generally true.  Cactus spines are actually the ‘leaves’ of the cactus: they’ve evolved to thin spikes to minimize the kind of moisture loss that is routine for broad flat leaves.  Cactus spines also deter predators (how many animals want to eat a needle-covered stem?)


Next I meet the unique marine iguanas for the first time. They are the only sea-going lizards in the world.  The iguanas are unique in  two other ways: they are the only reptiles on Genovesa, and they are the smallest reptiles in the Galapagos.  

Marine Iguana

And then there are the Swallowtail gulls, who are found only on the Galapagos and one other island (off the cost of Colombia).  The Swallowtail is the only known nocturnal gull, adapted for night hunting with large red-rimmed eyes.  The gulls survive eating fish and squid who make nightly visits to the water's surface where they hope to find plankton.

Note the swallowtail gull's large, red-rimmed eyes that make it easier to see well in the dark.

The gulls stand out with their black heads,  large, red-ringed eyes, white tails, and red webbed feet.  A couple will lay a single egg in a nest made of lava rocks (much sturdier than twigs).  Both parents remain at the nest during the day, taking turns brooding over the white and black chick. After dark, the non-brooding parent will take to the sea and forage all night

The light chicks are safe in the nest because potential predators are not night-time hunters. And the chick's bright appearance, which might seem like a handicap, makes it easy for parents to find their baby in the dark.  

The gulls also have an unusual shrieking call that helps it navigate, possibly because of the way the sound echoes off the rocky surroundings.

Pair of gulls,  one of our group in the background

One thing continues to fascinate me--the gulls, like the boobies we encountered earlier, are not intimidated by us.  I know much of their bravery has to do with the care taken to protect them.  But I'm still amazed at  how close we get to the wild life of these islands.

We make our way back to our starting point where we have the option of enjoying the beach, going for a swim, or snorkeling.   Whatever we do, we're walking into the water from the shore.   

Some years ago I learned to scuba dive, and to get my certification I had to walk in from the shore as well as flip myself into deep water from a boat.  I did both.  But here, now, I can’t get myself far enough into the water to appreciate the sea life.  Maybe the current is too strong?   Whatever the reason, I return to the beach a little disappointed, and settle for enjoying the view and the shore life until we return to the Letty.

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