A Blizzard of Butterflies

How lovely to go for a walk accompanied by a magical fluttering of yellowish-white butterflies. It is enough to make anyone feel like a Disney princess, or like Bambi exploring a technicolor forest.

In other years there have sometimes been sudden butterfly hatchings, but I have never seen so many, or for so long. It seems that when the heavy November rains broke our six month drought and trees were able to grow new leaves, that in turn created unusually favorable conditions for butterfly eggs to develop into caterpillars that could grow and thrive and produce an abundance of butterflies.     

Cluster of Great Southern White butterflies in Fish Bay  Photo Gail Karlsson
 Although there are several similar types of butterflies around, the ones I have been seeing the most are Great Southern Whites. You can tell because they have distinctive turquoise tips on their antennas. 

Close-up of Great Southern White on a branch
Photo Gail Karlsson

The Great Southern Whites are not special to the Virgin Islands. They are also common throughout the southern United States, South America and the Caribbean. Other Caribbean islands have reported mass hatchings this season as well.   

In the Virgin Islands, the Great Southern Whites tend to use the numerous, local limber caper trees as hosts. The females attach clusters of about 20 tiny torpedo-shaped eggs to the leaves of the tree – potentially producing up to 500 eggs each. When conditions are right, the eggs develop into caterpillars with black spots, dark hairs, and yellow stripes running lengthwise along their backs - much smaller than the well-known frangipani caterpillar. After two or three weeks of feeding on leaves, the caterpillar will transform into a chrysalis with a hard shell, usually hanging inconspicuously on the tree. After a week or so the chrysalis bursts open and the butterfly emerges. All in all, it is an amazingly complex process.   

Butterflies mostly suck nectar from flowers, using a long proboscis that they can extend and insert into the flowers. They are important pollinators for many plants, transferring pollen from one flower to another as they flit about.

The Great Southern Whites also seem to be social drinkers. I have often seen them gathering in groups along on our dirt road, apparently getting together to drink and draw minerals from the wet spots – an activity known as ‘puddling’.
Great Southern Whites puddling in the dirt road
Photo Gail Karlsson

Unfortunately these butterflies have a short life span. While they are here, they bring great joy to people on St. John, and we can hope for another big batch of them again – if all the eggs these ones lay are able to hatch, and there are enough leaves for the hungry caterpillars to eat, as well as nectar-filled flowers for the next generation of emerging butterflies.



War on Tan-tans?

Headline News:
Trump to Tan-tans “Go Back to Mexico!”
“They’re ugly, they don’t belong here, and they’re crowding out valuable native trees. They have no pretty flowers or tasty fruit, and they’re un-American. Let’s root them out now!”
Tan-tan (False tamarind)
Photo Gail Karlsson

Well, not really, though it does seem like if he knew about these invasive aliens, Trump would want to send them back across the border.  

It is true that St. John residents have been complaining about all the tan-tan trees sprouting up around the island after the abundant November rains. Known formally as Leucaena leucocephala, they are also called ‘false tamarinds’, as they slightly resemble (and may try to pass for) these ‘real’ trees. They seek out areas where the land is disturbed and spread their seeds widely, waiting for opportunities to take over new territory.   

The tan-tans were able to wait out the recent six month drought that brought down even some usually hardy native trees, and then sprang up with a vengeance when the heavens opened up in November. Once they put down their deep tap roots, it is extremely difficult to eradicate them. You cut them down but they keep on growing back. 

Local tree expert and historian Eleanor Gibney (though by no means a tan-tan supporter) reported that they were actually introduced to the Virgin Islands intentionally for an important purpose. During the mid-1800s there were a couple of thousand cows on St. John and the ranchers brought in the tan-tans as a fast-growing source of forage fodder. Some sources indicate that the trees probably came from coastal Mexico or Central America. Those deep tap roots allow them to survive the dry season, and to spring back to life after being chomped and stomped on by careless cattle. Some people still gather tan-tan branches to feed their goats, but mostly these trees are now viewed as undesirable aliens.    

Unfortunately, it would be too difficult to actually send all the tan-tans back to Mexico. More likely people will ramp up attacks on them using machetes, Round-Up and diesel fuel.     

Extermination efforts can lead to collateral damage, however, as many people have difficulty distinguishing between tan-tans and other similar-looking trees – including the amarat, a key hardwood species from the original Virgin Islands forests. Teaching people to distinguish these trees would help prevent indiscriminate damage to native hardwoods.  
The St. John Unitarian Universalist Fellowship’s Green Sanctuary Committee has recently started a project to raise awareness about the different types of trees commonly seen on St. John.
Anyone interested in learning more about local trees, whether native, naturalized or invasive, can connect with the project through its Facebook page UUF Tree Appreciation Project St. John VI, and website http://uufstjohn.com/treeproject/about/.
Can you identify these trees with leaves that are somewhat similar to tan-tans?



A. Tamarind
B. Amarat
C. Acacia

Snow Bird or Born Here?

Great egret hunting lizards in my yard
Photo Gail Karlsson
It’s not always so easy to tell the difference.
This is the time of year when seasonal migrants – birds and people – start showing up in the Caribbean. Many only stay for a brief stopover and then move on, but a certain number of regulars settle in for the winter, filling local beaches and watering holes and acting like they belong here.

Some permanent residents welcome the influx, while others wish the migrants would just stay where they were and leave the islands to the locals.

Of course it is sometimes difficult to distinguish locals from part-timers – at least among the herons and egrets.
In the ponds near my house on St. John I see great egrets, snowy egrets, and cattle egrets, as well as black-crowned and yellow-crowned night herons, green herons, great blue herons, and little blue herons. None of these are special types of birds that live only in the tropics. They can be found all along the east coast of the US, and lots of other places as well. But some of these birds are actually full-time residents of the Virgin Islands. How can you tell?

 Herons and egrets that breed in the northeast US during the spring generally move south in the fall, and a few might pass through or even end up in the Virgin Islands. Birds in warmer southern states don’t migrate in the same way. In the Caribbean, as well, some of the birds stay around all year, raising their young on island time. Their breeding schedule is linked to the wet and dry seasons that affect the availability of food here, rather than northern temperatures and ecological cycles. 

Raffaele’s book Birds of the West Indies identifies a number of birds in the heron/egret family as “common residents” that live and breed here: snowy egrets and cattle egrets, green and little blue herons, and yellow-crowned night herons.

Great egrets are considered “uncommon residents” in the Caribbean.

Last fall I saw flocks of great egrets gathering in Jamaica Bay in New York City at the end of September, and then one day in early October woke up to find a bunch of them sitting in the trees around the pond by my house in Fish Bay. It seemed like we were on the same flight path.
Photo Gail Karlsson

After a few days most of the great egrets were gone, but a couple seemed to be fishing in the pond all winter. Were they on St. John all along, or did one pair of migrants settle down in the neighborhood for the season?
Great egret couple in Fish Bay pond
Photo Gail Karlsson
You would definitely be sure that an egret is living on St. John if you could find its nest. Up north, I have seen large numbers of nests all built close together in one or two trees, since there herons and egrets usually breed in colonies in the spring and stick together for protection. An ‘uncommon resident’ couple might end up nesting alone though, and at a different time of year. I have gone around looking for great egret nests in marshy areas of St. John, so far without success. If they are here, they are pretty well hidden. 

There is another indication, though, that a great egret is a resident: if you see breeding plumage. I have definitely seen birds in the pond with the long, lacy breeding feathers that are called aigrettes. (These plumes became popular for decorating ladies’ hats in the late nineteenth century, and during that time egrets were hunted almost to the point of extinction.) 

Photo Gail Karlsson

So I do think at least some of the great egrets I see are permanent residents. Others, like me, travel back and forth, attracted to the warmth of the tropics, but not content to stay in one place all year. As Joni Mitchell wrote: “They got the urge for going, and they got the wings so they can go.”