Green Heron Observations

Green herons sit patiently and watch intently.  

Instead of thrashing around in the pond, sometimes it is better to just be still and quiet, waiting for an opportunity to arise. Like a fish swimming by. And then be ready to spring into action.

A green heron can move quickly and decisively when the time is right.

 

Green herons are also famous for using tools - dropping leaves or bugs into the water to attract fish, then picking up and repositioning the bait as needed. Very smart. I have only seen videos of this, though. Maybe the green herons I’ve watched have had plenty of fish and didn’t need to work that hard. 

 

Sometimes patience is all you need to catch a big fish.

Often people make up names that are meant to be descriptive but don’t really fit. There aren’t really many green feathers on a ‘green’ heron. To me their back and head feathers look more blue, and their necks are rusty red.

 

Those necks You can see better if you stick your neck out. 

And it can be convenient to just lean down and suck up a fish for dinner. 

But sometimes it’s good to blend into the background. Rusty striped neck and chest feathers can provide camouflage when the green herons are lurking by the edge of a pond.  

There are green herons that live in the Virgin Islands all year, and a few others that come down for the winter. The permanent residents live in the wetlands and make nests out of sticks, either on the ground or in trees. 

Usually the green herons keep their nests pretty well hidden. However, Laurel Brannick recently saw one with a nest in plain view, hanging out on a branch over the Francis Bay pond on St. John. 

Photo Laurel Brannick

The exposed location was probably not the best choice. Laurel thought she saw two chicks in the nest, but by the next week the nest was empty.  

Why Don’t Hermit Crabs Make Their Own Shells?

 

Hermit crabs have hard claws and legs, but soft abdomens they stick inside abandoned mollusk shells.

I enjoy having hermit crabs in the yard. They are known as soldier crabs in the Virgin Islands, but are not aggressive. They are generally cute and fun, and come by to snack on leftover cat food. 

Cats may not be so happy to see these intruders. But even if they catch a snacking hermit crab red-handed, they can’t do much damage to it when it's drawn up inside its shell. The hermit crab can stay inside its shell until the cat gets bored and leaves.  

 

Even when hermit crabs hide inside their shells, though, their legs and claws usually stick out some. As they grow larger, their legs and claws hang out further, and they have to start searching for a bigger shell.  

 

Recently I started to wonder why, after over 150 million years, hermit crabs are still scrounging around for discarded mollusk shells to cover their butts. 

 

Caribbean hermit crabs, or soldier crabs, (Coenobita clypeatus) commonly use cast-offs from West Indian Top Shells (Cittarium pica), otherwise known as whelks or wilks.

They are called ‘top shells’ because they resemble small spinning toys. 

 

West Indian Top Shells, like other marine snails, build an exterior exoskeleton through a process called biomineralization. They have an organ called a mantle that secretes a thin layer of protein as a base, followed by layers of calcium carbonate, which they create using carbon and calcium ions drawn from the seawater. The calcium carbonate then solidifies to make the hard shell. Later on, the mantle can add to the edge of the shell, so the same shell can grow as the snail gets bigger. 

Most crabs also use calcium carbonate to make hard shells for themselves that cover their whole bodies. But their shells are fitted to their legs and bodies, and not expandable. In a process called molting, as the crab grows bigger, it forms a new, thin exoskeleton cover underneath the existing shell, and breaks out of the old one. Once out, the crab then quickly makes the new, soft exoskeleton harder using calcium carbonate.    

 

Hermit crabs do the same kind of growing and molting as other crabs, but only their claws and legs get hardened up. The abdomen stays soft and the hermit crab needs to find a new larger shell to cover it. The shells provide protection from predators and also prevent them from getting dried out and cooking in the tropical sun. 

They do briefly take their shells off to mate. A male hermit crab will tap on a female’s legs to persuade her to come out and mate.   

 

Female hermit crabs make a group pilgrimage down to the shoreline to deposit their eggs in the water. There the eggs go through several free-floating phases of development before the baby hermit crabs start their transition to land. While in the water, they need to locate a discarded shell from a (dead) micro-mollusk, which are species of snails that remain tiny even as adults. Over time they will then work their way onto land and into ever larger shells.

Depending on finding abandoned shells from other dead animals seems pretty iffy as a life strategy, although it does allow successful hermit crabs to avoid spending a lot of energy building and maintaining their own mobile homes. They are renters, not owners, which in some situations can be an advantage. 

 

Still, the hermit crabs are heavily dependent on continued housing availability. There needs to be a large population of whelks – and intact shells left behind after they die or get eaten. In the Caribbean, an octopus or lobster will eat whelks, as well as bonefish, porcupinefish, and rock hinds. The whelks are also attractive to shorebirds like oystercatchers, which are locally known as whelk-crackers. And then there a number of people who collect whelks for stew. Supplies of whole, empty shells can quickly become limited. 

 

Hermit crabs are essentially recyclers, taking cast-off resources and reusing them, and in the process cleaning up the beaches. If they can’t find a shell that fits, they will sometimes end up wearing beach trash instead, which is a bit sad to see, but adaptive and enterprising of them. 

 

A hermit crab’s survival plan is also a bit poetic, as each temporary shelter it finds will carry a history of prior lives, which it will carry on its back, and then pass along.

 

 Small hermit crabs use shells other than top shells.

Laughing Gulls Try To Steal Fish From Brown Pelicans

  

A laughing gull landed right on top of this brown pelican.

I have seen laughing gulls drop down onto the backs of pelicans and try to grab fish as they fall from the edges of the pelicans’ pouches.   

 

Sometimes fish do escape from a pelican’s mouth.

 

A pelican will fly high over the beach scanning for movement and then dive quickly down into the water, scooping up small fish in its pouch. Then it will lift its head to drain the seawater out of the sides of its pouch before swallowing its catch. That’s the moment when the laughing gull will try to snatch a fish.

  

A laughing gull needs to get very close to the pelican’s pouch to check for dropped fish.

 

I learned a catchy name for this behavior – kleptoparasitism. 

 

The laughing gulls can be quite intrusive but pelicans are large birds, and an angry pelican can deliver a sharp bite with the hook at the end of its beak – though not when its mouth is full.

 

A pelican mostly uses its pouch like a fishing net.

 

And when a laughing gull approaches from behind, it is hard for the pelican to get the gull off its back.  

Sometimes it looks like the laughing gull is getting into a mating position.

 

One passive pelican defensive strategy is to just keep its mouth closed until the laughing gull gets bored and goes away. 

 

  

 Are they sharing feelings?

 

Another pelican strategy is to make itself look a big crazy turtle.  

 

 

 A laughing gull will eventually get fed up.

 

I find it hard to understand why the laughing gulls don’t just go catch their own fish. Are they just being lazy? 

 

Maybe, but this behavior actually seems to be an evolved strategy. A pelican can dive deeper and get more fish than a laughing gull. So a laughing gull that is able to get some of the pelican’s fish without too much trouble can be more successful – eating better, conserving its energy, and having more time for mating, nesting, or defending its territory. 

In the spring, laughing gulls often are busy mating on top of buoys.

 

It is actually not just laughing gulls that try to steal fish. I once saw a huge frigatebird at Maho Bay attack a small tern sitting on a buoy until it gave up the fish in its mouth. That was a violent form of theft. Also, up north, bald eagles will grab fish from ospreys in a mid-air display of their superior strength.  

 

The laughing gulls can’t take a fish from the pelican by force so, while annoying, they are probably not really scary. And, to an observer, they do look pretty funny riding on the pelicans. 

 

A waiting game

Kapok Seeds Fly Off in Fluff Balls

 

Fuzzy kapok fluff contains small seeds. 

After witnessing the weeks-long spectacle of a kapok tree (Ceiba pentandra) attracting a mob of bats to pollinate its flowers (see my May 17, 2025, VI Source article if you missed it), I kept going back to see what would happen next. 

 

After the bats come to eat the nectar inside the flowers, and consequently spread the pollen around to other flowers, the flowers fall off. Then the kapok tree’s seeds begin developing inside the cup-like structures where the ovaries are located. 

The spaces left where flowers fall are soon filled with developing seed pods.

  

 

Since there are lots of flowers on the tree, and they aren’t all pollinated at once, some of the seed pods start growing sooner than others. At first, the pod is green and looks like a tiny zucchini. When it gets bigger, the pod turns brown and hard. 

Successfully pollinated flowers go on to produce seed pods. 

 

 

I kept going back to see how the pods were developing but it was many weeks before I saw any of them opening up. Eventually they started cracking open lengthwise, and I could see rows forming inside that from a distance looked like kernels of corn growing on the cob.

 

The expanding fibers around the seeds pushed open the pods.

 

  

After the pod’s hardened skin dropped off, you could see that the ‘kernels’ were actually soft. Soon wisps of the compressed fibers started getting loose as the wind caught them.  

The fibers around the seeds kept expanding once they were free of the pod.

 

 

For a while the tree looked like it was decorated with round puff balls. While many other types of trees get their seeds distributed by producing tasty fruits for birds and animals to eat and deliver to another spot that might be favorable for germination and growth, the kapok trees instead send their seeds floating off on fluffy parachutes. 

The kapok tree didn’t use up its energy growing new leaves until the seed development process was over. 

 

 

 

 

 

 

 

 

 

 

 

 

 

As the fibers got fuzzier and kept expanding and getting looser, some of them kept their ‘kernel’ shape, just growing bigger and softer. Later, they lost it entirely and completely unraveled. Then you could see that there were small, dark seeds attached to the fibers. Because of these fibers, the tree is also sometimes called a ‘silk cotton’ tree.  

 

 A light waxy layer on the kapok fluff makes it shiny and water repellent.

 

 

For many years the kapok fibers were prized by people for use in life jackets and life preservers because they are very light and buoyant and do not absorb water. At the same time, the fluffy fibers trap air, so they retain heat and are useful for insulation and bedding. Over time, people started using synthetic substitutes, but there has been some interest in kapok again as a natural, non-allergenic fiber.   

 

The primary purpose of the light-weight fluff, however, is to transport the little seeds through the air to a space far away from the mother tree where another such huge tree could possibly grow and thrive.   

 

Unfortunately for many of the seeds, and the homeowners nearby, much of the fluff ends up just falling close to the tree, on top of other trees and bushes, or smothering the existing ground cover plants.  

Globs of fallen fluff can end up covering the ground and other plants.

 

I hope that some of the seeds do reach a good place for them to grow, so there can be more of these wonderful trees around to support local wildlife, and to delight human observers as well. 

Viewing Seabirds on Offshore Cays with St. John Students

 

The students got a close look at a Royal Tern sitting on a post in Cruz Bay. 

Third graders from Gift Hill School had a chance to check out summer seabirds congregating around Congo Cay, Lovango and Carvel Rock through a V.I. Audubon Society program supporting education about local birds. The school bird program just began this year and is expected to soon include classes in other grades and schools. 

Last summer the third-grade teacher, Mrs. Wallace, attended a Birds Sleuth training course offered by the BirdsCaribbean network and then put together a curriculum plan appropriate for her students. 

V.I. Audubon board member Laurel Brannick was the trip leader. Laurel served as a National Park Ranger on St. John for 30 years before retiring, and now offers regular Friday morning bird walks at Francis Bay, as well as Thursday evening slide shows at Cinnamon Bay Campgrounds. 

I went along on the boat trip to try to get photos of the migratory birds that come to the small islands off St. John during the summer months to make their nests.  

In April, we usually start seeing black-headed Laughing Gulls arriving along the beaches of St. John from other areas in the Caribbean. They are attracted by the abundance of small fry fish at this time of year, and the relative safety of the uninhabited offshore islands for nesting. 

Laughing Gulls 

In May, the gulls are joined by flocks of graceful Roseate Terns with mostly black bills. 

Roseate Terns 

Sometimes the Laughing Gulls and Roseate Terns hang out together to fish along St. John shorelines. 

Laughing Gull sharing a rock with three Roseate Terns 

Soon, however, both types of birds start thinking about nesting, and then the Roseate Terns try to stay away from the Laughing Gulls, concerned about attacks on their chicks. 

Roseate Terns nesting on cliff on Congo Cay

Close to the top of Carvel Rock we also spotted other related nesting seabirds I hadn’t seen before – Bridled Terns.  

Bridled Terns rarely come close to the shore of St. John

The highlight of the trip for me was when Laurel pointed out a couple of birds flying way up in the clouds and said she thought they were tropicbirds. These have been sort of mythical birds for me because I had never seen them on St. John, even though some people have reported seeing them from boats or flying around the rocky cliffs.  

The birds Laurel pointed out looked like large terns with just the slightest trace of the long ribbon-like tails the tropicbirds are known for. I took a couple of shots with my telephoto lens, but didn’t have high hopes for good results given their distance from us, the cloudiness of the day and the rocking boat. Still, I did manage to get an image of what seemed to be a Red-billed Tropicbird, which made my day. 

Red-billed Tropicbirds are more common here than the white-tailed ones. 

I probably enjoyed the boat trip more than anyone, because I was able to use my camera lens to zoom in on the birds. But the students did get a chance to see the remote places where seabirds hang out around St. John, and maybe will want to learn more about what the birds are doing out there. One of the students remarked on the beauty of the undeveloped cliffs along Congo Cay, and Laurel emphasized how important it is to preserve at least some spaces just for birds and other wildlife.   

Amazing to Witness the Pollination of a Kapok Tree

Kapok trees in the Virgin Islands attract local leaf-nosed fruit bats (Artibeus jamaicensis)

One morning at the Unitarian Fellowship meeting my friend Kim mentioned that the big kapok tree by her place nearby was in bloom, and invited us to come over that evening to check it out. We needed to wait until dark because the flowers only open up at night, to attract the nocturnal fruit bats that are their main pollinators. 

This kapok tree is huge, and dominates the skyline. 

Kapok trees can produce thousands of flowers all at once.

I had read that kapoks, also known as silk-cotton trees (Ceiba pentandra), were viewed as sacred trees by the Tainos, the early inhabitants of the Caribbean islands who came up from South America. The Tainos were probably traveling in dugout canoes made from thick kapok tree trunks, and carrying the seeds with them. Reportedly, the Tainos revered the bats attracted to the kapok tree flowers as the spirits of the dead that offered a connection between those still living and the world beyond.  

However I had never actually seen the bats showing up at one of the trees. The kapoks don’t flower very often, and then it’s not always okay to go around looking for bats at night, especially on other people’s property. So we were grateful for this invitation.   

When my husband and I arrived after dinner, it was already dark, a bit late, and it was hard to figure out what was going on. Small areas of the tree were being lit up by other people holding flashlights, and bats were frantically flying around the flowers that were already open. Someone pointed and yelled out ‘there’s one’’ and then that bat quickly sped off and other ones whizzed by out of the shadows. As they flew around they were knocking off dead flower heads, which showered down on us, along with occasional bits of nectar-scented poop. Good to have a hat on.  

I had my telephoto lens with me, which requires two hands, and I couldn’t hold a flashlight as well. Also, I am not skilled at shooting in the dark, and had trouble focusing on the spots people were pointing at before the bat and circle of light had moved on. 

It was all very frustrating and confusing until the tenants on the third floor invited us to come up and look at the mid-level of the tree from their deck. Up there, the bats and flowers were much closer. And one of the tenants was kind enough to hold her flashlight on a few nearby bats long enough for me to get some in-focus photos of them drinking nectar from the center of opened flowers. 

  

By about half an hour after we arrived, the bats seemed to slow down, maybe because they had already drunk a good bit of nectar from the flowers. Instead of zooming around like crazy, they started dropping down and lying on top of clumps of the opened flowers with anthers sticking up full of pollen. 

By then the bats’ faces and brown fur were covered with the yellow pollen. 

The blooming and pollination process lasts for a few weeks as different sets of flowers on the tree open sequentially. Even though it seemed like there might have been over 100 bats coming to feed, they needed to keep coming back to get around to pollinating all the flower bunches as they opened. The tree had to produce a lot of nectar to keep them coming. Once this frenzy of activity was finished, it might be years before the tree would have the strength to bloom again.  

After that first night I went back a few more times to try to understand more about what was happening, arriving well before dark to be ready when the bats started coming. 

I prepared by going to the hardware store to get a strong flashlight. They recommended one called ‘Big Larry’ and I enlisted my husband to hold it steady while I tried to get photos of the bats in flight. The people with the balcony were no longer there, so I tried to find a good viewing spot from the ground. There were some relatively low-hanging branches with flowers, but unfortunately, Big Larry’s beam could not really reach that far. 

The next day I went back and found an even stronger flashlight – all business, no nickname. 

My husband held the flashlight as I tried to video the bats with my phone. (Photo Joan Farrenkopf)

That night I invited the visiting speaker for the Unitarian Fellowship to come with me, because she had missed the first night’s visit. It was particularly thrilling this time because when the bats came several of them swooped down low and circled us. In the dark I heard her exclaim “Mon dieu, il m'a touché”. When I looked over she was rubbing her arm and said she was so surprised she lost her English and reverted to her childhood French. Another night I promised a different tree-loving friend ‘a life-changing experience’ and she was not disappointed. 

  

The bats were not the only creatures attracted to the tree’s flowers. When I went by one day in the late afternoon, I could see that bananaquits were investigating the buds. Some bananaquits seemed to be trying to pry open the flower’s tips. Others were more aggressive, poking their sharp beaks into the sides of the flowers as a short cut to getting at the nectar sac without providing any pollination services in exchange. 

Bananaquit preparing to pierce a flower to reach the nectar

Later on, hummingbirds tried to sneak their long, skinny tongues into the flowers, just as the petals started to crack open.  

An Antillean crested hummingbird explored the opening flower buds

At dusk, hummingbird moths and bees gathered around as the scent of the opened flowers started spreading through the area. I though the bees would be sleeping by then, but I guess this was an opportunity worth staying up for.

 

What an adventure to stand underneath this marvelous tree at dusk and join the wild company drawn to its exuberant blossoming. 

And then, when it got dark and the bats arrived, there was a wild frenzy that made my heart race. My time there certainly felt like a spiritual experience, connecting me with so many other ways of being in the world, in the night, on this island. 

A pollen-covered bat stood still for an intoxicated moment before flying off