Thursday, June 1, 2023


Wednesday night, we watched a video on sea turtles and egg harvesting at Ostional.

The next few pictures are from the video.  During the Fall, egg laying is at it's peak.  Local residents work together as a community to harvest between 1 and 10% of the eggs, which provide a source of income for the community.  The largest Arribadas (mass turtle egg laying event) occured 1995 when about 500,000 turtles came ashore to lay their eggs.  There are so many turtles, they continually dig up each others nests, scattering eggs everywhere, which are quickly devoured by predators and scavengers.

After 40-50 days, the young turtles hatch, crawl to the surface, and make a run for the sea.  There are many predators, chief among them the black vulture.

This picture shows people harvesting eggs.

In addition to harvesting some eggs, the locals serve as rangers, patrolling the beaches to prevent poaching, they clean debris from the beaches to help turtles access the beach, and they scare away predators from both the eggs and the baby hatchlings.

At 7:00 pm, we went on a night-time turtle walk with four guides.  The beach closes at 9:00, so we didn't have much time.  We walked quite a ways on the beach and sat and waited for guides to spot a turtle.  We waited.  And waited.  And waited.  Then suddenly, one of the guards from down the beach started flashing his light.  A turtle had come ashore.  We ran that way, and this is what we saw (the guide used a red light to keep from disturbing the turtle.  Flash and white lights were not allowed):

The female crawls up the beach and digs a hole about a foot and a half deep with her hind flippers.  This turtle was about 3 feet long.  She is an Olive Green Sea Turtle.  The whole process takes about an hour from coming ashore to going back in the ocean.

Digging.  A group of researchers came up, and sort of crowded us out of the way to take measurements of the turtle, and to band her on her right front flipper.  She laid eggs for about 15 minutes, then covered them up with sand.

At that point, we had to leave the beach because it was almost 9:00.  Since we were cutting it very close, the guide took us further down the beach toward another exit...except right then, a terrific rainstorm hit.  We got soaked through and through, but when we made it to the road the owner of the guide shop met us with a pickup truck.  We were seriously happy to see that and piled in the back for a ride home in the rain.  An amazing and lucky evening.  We wished the turtle and her young-uns good luck.

I wanted to share a few photos of Ostional.  This is the entrance to our hotel.  Nosara, down the coast, has become a popular neuvo-hippy-trust fund tourist destination with yoga and coffee shops and million dollar properties.  Ostional is sort of a remnant of what the coast once was, protected by the roads I covered in my bus blog.  I tried to stress to the students that they were lucky to experience this window in time...even with all it's bugs, wonky hot water, and the like.  I don't think it will look like this in five or ten years.  Property up and down the dirt roads is for sale.

Here's Windy, the owner of our hotel.

The street leading to the beach.

The main road.

I guess this is an abandoned house, but I was struck by how someone made cool designs on it using shells pressed into the stucco.  It's hard to see the detail in this picture.

Here's a closeup of part of it.

These is one of the black vultures that make a living eating the turtle eggs.

Thursday morning, we drove to the dry forest and went for a hike.

Bullthorned Acacia.  This is an interesting plant.  Ants live on the plant in those thorns.  The plant makes a sweet substance that the ants eat.  In return, the ants attack any herbivores that try to eat the plant.  The ants also "prune" away other plants that touch or even get near the acacia so it doesn't have to compete with them.  So, it's a situation where both species benefit.  This is called mutualism. Can you spot the ant in this picture?  Me neither.  They are there.  Trust me.

This is kinda cool.  You can see the circular cutouts from where leaf-cutter ants cut pieces out of this leaf.

Mark explains adaptions of trees to dry forest conditions.

There was a dry slough which was muddy, and we had to cross it on the slippery log rounds someone put out.  On the way back, the tide had come in a bit, and the water was about a foot deep everywhere making it....interesting.

Big mangrove tree.
Dr. Parshall

Dr. Parshall trying not to slip.  Parshall and I have had an on-going disagreement on the best footwear.  He swears by these rubber boots.  I'm usually wearing some old closed toe Birkenstocks.  He's right, and I'm wrong, but don't tell him that.

Danielle showing what happens when you do slip.

A lot of trees have adaptations to store water.  This one sounded nearly hollow when we tapped it on the side.

It's real hard to get pictures of Daniel.  He tends to keep moving on.

A Blue Morphos butterfly.  They live just a few weeks.  This one is getting old, you can see how tattered the wing edges are.

The underside.  Mark says the eye spots are designed to get predators to try to hit them, and not the juicy yummie body bit.  Generally birds go for eyes, because that's where the best of the bug is.  You can see how this one is tattered.  I have to reduce the resolution of these photos a lot to make them small enough to post on the blog, but if you enlarge it, you can probably still see the scales...about 400 scales per square mm of wing surface.  These have a prism effect (like the hummingbird wings discussed earlier), and that's what gives the Blue Morphos is iridescent blue color.

Each ring on this cecrotia tree shows where a leaf was attached.  The rings are far apart during the rainy season and close together in the dry season.  It grows about 1-2 meters per year.


After a lunch of pizza, we boarded kayaks and headed for a nearby estuary to explore the mangrove swamp.

This is a view from my foot-cam.

Our guide Kevin was awesome.

The mangrove trees are really cool, with many adaptations for the roots to breath air, even as the water levels go up and down.

After a bit of paddling in the estuary, we pulled over, walked across the sand, and to the Pacific Ocean on the other side.

Olivia found this fiddler crab.

The guide cut open coconuts for everyone, and we enjoyed a drink of coconut water.

On the way up, the guide had us be quiet and move to the side of the estuary, because there is a crocodile nest.  As you well know, that's an old trick used by guides to scare the gringo tourists and build drama.  On the way back, in a bit of a rainstorm, I snapped this picture of one of the babies up on a log.  I did mention that Kevin was an awesome guide, didn't I?