Have You Found Birds Nesting­ on Your Deck?

Two bullfinch babies quietly opened their mouths hoping for food

 

When we came back to our house late last month, I saw that there was a nest in the corner rafters of our screened-in deck downstairs. We had left a door open at one end while we were gone so it wouldn’t be blown out if a bad storm came by. We soon discovered that a couple of Lesser Antillean Bullfinches had used the cozy deck area during our absence. 

 

When I first noticed the nest, I assumed it was empty. I didn’t see any birds around, and it was right above where we usually sit to eat dinner, so I was planning to remove it. 

 

However, when I stood up on a chair and peeked inside, I thought I saw something moving down in the bottom. I looked more closely, and saw a small, gray, slightly twitching pile, and an unopened eye on what seemed to be a newly hatched chick. Oh dear.

 

When there is consistent warm weather and an abundance of food, most resident birds can breed throughout the year. In the past we have come back in the fall and seen remnants of nests around the house, but mostly by late October the birds were finished, and the nests had fallen down. They never really seemed very sturdy anyway.

 

You can see both the parents gathering material to build nests and working on it clumsily, apparently without a lot of construction expertise. Still they do manage to reproduce successfully and are abundant on many of the smaller eastern Caribbean islands. 

 

The females are light colored, with a mix of tan and beige feathers. 

A female bullfinch gathered nesting material from a pygmy date palm tree

 

The males are black with red patches on their throats, above their eyes, and under their tails. They are quite aggressive, at least about boxing out the Bananaquits at the sugar feeder when I fill it. Yet it turns out they are good partners and providers when it comes to parenting.  

 

Male bullfinches also bring sticks for the nest.

 

We mostly stayed off the deck after I looked into the nest. From inside I saw both parents through the screen. They seemed to be consulting, and then decided that it was okay to fly across the deck to the nest. We were hot and dark inside, though, so I did sometimes open the door from the kitchen to get some more air and light. 

 

One day about a week later I looked out and noticed something moving in the nest. Of course my first thought was to get my camera. Sitting far back inside the house, I used my telephoto lens to check things out from a distance. Now the nestlings had gotten bigger, and I saw two mouths sticking out of the nest, not making any noise yet, but obviously hoping one of the parents would come with food. The babies’ mouths have yellow lines around the outside, and are bright red inside, so the parents have clear targets for dropping the food.   

 

I figured that one of the parents would show up soon, so I sat there very quietly, holding my camera. I actually had to wait for almost an hour. A wildlife stakeout operation in my own kitchen. Then suddenly the dad appeared with some food in his beak, and when I raised the camera to take a photo, he turned and gave me a hard look. 

 

The bullfinch father came by to feed the babies

 

After that look, I kept all the doors to the deck closed. I didn’t want the parents to get scared off and abandon the nest. I couldn’t see very much from inside, so I wasn’t sure what was happening. At one point the nest seemed to be falling apart, and I wondered if the parents were still coming.  

 

Then about two weeks after we got back, I saw some movement outside the nest. I opened the door to the deck, and just then a baby bird dropped onto the chair below the nest, and then flopped onto the floor. 

 

When the baby bird dropped out of the nest it couldn’t fly

 

I was worried about its safety, but the dad quickly appeared and gradually led the baby along the deck and out the door into the low bushes next to the house. I was very relieved. 

 

There was no further activity around the nest after that. I hopedt that the other baby had already fledged while I wasn’t around. I was also happy to be able to open the doors so we could use the deck and cool down the house a bit.  

 

I could still hear them calling to each other outside though. Like many other young birds, the bullfinch babies will beg for food from the parent for quite a while, even after they have learned to fly.  

A hungry bullfinch chick appealed to its mother for food 

 

It would be interesting to hear about any birds that have chosen to nest on your decks.

      

 

Yellow-rumped Warblers Could Be On Their Way To The Caribbean

 

Yellow-rumped Warbler

I am wondering if they will make it as far as the Virgin Islands this season. 

 

Last year I saw quite a few of them migrating through New York in late October, and then soon afterwards I thought I saw one flitting around the sugar bowl on St. John. But then I realized it was one of the resident Bananaquits, which are about the same size. 

 

You don’t often see Bananaquits showing their flashy yellow backsides, because their wings close over their butts when they sit down. But wow, when one flies up with its back towards you, there it is, so don’t get confused by them. 

    

Bananaquit

 

During the summer, the Yellow-rumped Warblers breed in Canada and down into New England. Then in the fall they start to migrate further south. They tend to leave their summer places later than other warblers, often in October, and then they go back north again as early as March or April. 

 

Yellow-rumped Warblers breed in northern coniferous forests.  

 

Members of the subspecies of the Yellow-rumped Warblers on the east coast of the US are called Myrtles, and those are the ones that show up in the Caribbean. But some of them just stay along the east coast for the winter, not even going very far south. 

 

In the Virgin Islands, they are ‘irruptive’ - usually rare but then some years showing up in a big bunch.  

 

It seems a bit of a mystery why some of them stay in the states, while others come down to the Caribbean, and then occasionally keep traveling this far. Winter migration is mostly about food, not warm weather, so it might be because some years there is not enough food in certain areas, or perhaps there are too many birds clustered somewhere along the pathway and so the later arrivals just keep on going. 

 

Like most warblers, they primarily eat lots of insects. Not sugar, so they will not come to the sugar bowl. During the spring and summer, they forage on the ground, and in trees, and also grab bugs out of the air. 

 

Yellow-rumped Warbler pulling a worm out of the ground

 

But Yellow-rumped Warblers are more versatile than many other warblers. They can digest berries too, and that allows them to spend the winter in cooler areas that have winter berries, even after the insects get scarce. 

 

Yellow-rumped Warbler eating berries

 

A few years ago I did actually see a large flock of Yellow-rumped Warblers on St. John, in the mangrove wetlands near Annaberg. They were creeping around on a stand of dead trees and seemed to be picking through the spider webs, eating trapped insects and maybe the spiders too. 

 

Yellow-rumped Warbler finding insects in spider webs in the mangroves

 

Often called ‘butter butts’ by birders, these are among the most common and widespread warblers in North America. Their numbers have not been decreasing, unlike some other types of migratory birds. 

 

However, there was an incident in Chicago recently where many of them died, along with other warblers, when they collided with a building. Most warblers migrate at night, and can become disoriented by brightly-lit buildings. They sometimes also get confused when they are looking for food during the day and fly into glass windows that reflect trees, which knocks them out. That is why people in many areas along the migratory bird routes are currently pushing for legislation requiring buildings to adopt bird-protective measures. 

 

It is possible that only a few Yellow-rumped Warblers will get down here this winter, but I’ll be keeping a lookout for them. And let me know if you see any.

Are Those Fiddler Crabs Waving at Me?

 

A male fiddler crab has one large claw that he waves around.

I mostly see these tiny crustaceans along the edges of the salt ponds. There might be hundreds of them in a small area, and some of them are enthusiastically waving their claws in the air.

They are so cute that I want to get close enough to check them out.  But when I approach, suddenly they are all gone. Even when I move very slowly and quietly. Fortunately, when I am out on bird walks at Francis Bay, I can sometimes catch pictures of them with my telephoto lens before they disappear into tiny holes in the mud.

The crabs each have a hole in the mud close to the edge of the water where they can drop down and hide. Predators like herons, egrets and clapper rails feed along the edge of the pond and will snap up these little crabs like popcorn if they don’t hide quickly enough. So most of the time the fiddler crabs stay close to their burrows.  

The burrows are up to about a foot deep and besides providing the crabs with shelter, they also help the mangroves trees around the pond by watering and aerating their roots.

This fiddler crab found a cozy spot in a relatively dry, pond-side area.

One time I saw a group of fiddler crabs out in the deeper water hanging onto a branch. I was happy to have them out of their burrows and sitting in plain view for a change, but it didn’t seem very safe. Maybe they were forced out of their burrows by a heavy rain and were clustered together on the branch for protection.

These fiddler crabs were hanging out just above the surface of the water. 

It is only a male fiddler crab that has the one oversized claw, and when he is waving back and forth it is usually in hopes that a female crab will come into his burrow. Sometimes the males will also use their claws to keep rivals away from their territory, or even fight each other.

The females have two small claws, but when I was looking through my photos, I couldn’t find a clear image of a female fiddler crab, only a few blurry ones. Maybe the females are more reclusive, lounging down in their burrows.

When a female is ready to mate, though, she comes out of her burrow and walks around the neighborhood. At that point she is very vulnerable to predators. As she quickly scuttles around, she is looking for a male with a good-sized claw. When she finds an acceptable one, she will follow him into his burrow to mate. 

Interestingly, some male fiddler crabs are born with their large claw on the right, and others have the big one on the left. I have seen both kinds. It’s not clear whether the females have a preference. 

 

A few males might lose their big claws somehow. Maybe from fighting, or escaping a predator, and in that case the smaller claw (on the other side) can grow larger to take its place. 

The other prominent feature of these crabs is their eyes. Many crabs have their eyes on stalks that stick up on top of their heads. But these fiddler crabs are very small, and their bodies are often obscured by the big claws, so mostly all you see is eyes and claws.

Those high stalks allow them to get a long-distance perspective. That’s why they know to hide when I am approaching but not yet close. They don’t have great visual focus at a distance, though, so they probably can’t actually tell the difference between me and an egret. 

Their compound eye structures also give them a panoramic view, so they can see what’s behind them without moving their eyes or turning their heads, and can see what’s around them both on land and under the water. Scientists have become interested in studying the structure of fiddler crab eyes as they design complex artificial vision devices and robotic applications. 

Fiddler crabs are exposed and vulnerable when they are out on the mud flats.

When I tried to figure out what species of fiddler crabs I was seeing at Francis Bay, I found some pictures on the Internet that made me think their scientific name might be Minuca burgersi, which is one of the common types in the Virgin Islands. I was mostly focusing on their reddish color. 

For confirmation, I asked some local nature experts, including Caroline Rogers, a former research biologist with the USGS Wetland and Aquatic Research Center. She contacted Paul Jobsis at UVI, who forwarded my photos to several others, including a UVI professor, Guilherme Corte, who in turn connected me with Helio Checon, an ecologist in Brazil. Checon informed me that the claws (and the teeth on them) are key to identifying different fiddler crabs - more so than coloring. Though most of the crabs in my photos do seem to be Minuca burgersi, the claws on the ones in the first photo look heavier, and Checon suggested those are a different species.   

Despite their big claws and sophisticated eyes, quite a few fiddler crabs get picked off by birds foraging along the edges of the ponds. Fortunately, however, there are still many of them around. Be sure to give them a wave from a distance when you see them.   

 

Seeing Zenaida Doves, Not Mourning Doves, in the Virgin Islands

 Zenaida Doves show white patches when their wings are folded

There are two closely related types of doves that look very similar. But Zenaida Doves (Zenaida aurita), are only found in the Caribbean area. I first noticed them hanging around on our dirt road and then flying up just as I came by in my jeep, making a whistling sound with their wings, and then sometimes flying alongside the car for a few seconds. They seem to like foraging in the road. 

 

Mourning Doves (Zenaida macroura) are similar but are more widespread. They are residents across much of North America, and I recently learned that they also live in the Greater Antilles, as far east as Puerto Rico. In addition, some of them are northern breeders that migrate down into the Caribbean in the fall. So I suppose it is not impossible that a Mourning Dove could show up in the Virgin Islands at some point, though I haven’t seen one here yet.  

 

How do you tell them apart?

 

The most obvious difference is that a Zenaida Dove has white tips on its wing feathers that show up as a white patch or ‘check’ when the bird is standing. 

 

Mourning Doves don’t have the white wing patches

 

It is fairly easy to see the white wing patch (or lack of it) from a distance. It would be harder to notice that the Mourning Doves are also a bit larger, and browner, with lighter bellies and longer, pointy tails. The rings around their eyes also seem bluer.

 

Both types of doves have similar five-note cooing calls, which can sound sad, though some people confuse their ‘hoo-Hoo hoo-hoo-hoo’ with owl calls, which are not considered particularly melancholy.  

 

For both types of doves, the males have iridescent purple feathers on their necks, which are most visible when they are cooing loudly, puffing out their necks and trying to impress the females. (In the Virgin Islands, the breeding season for Zenaida Doves is from May to August.) 

A male Zenaida Dove displays his iridescent neck feathers

 

I also recently learned that doves are not really so peaceful – the males will sometimes fight during breeding season. Last April, a reader on St. John, Susan Crane, sent me a video from a driveway camera showing two blurry smallish, brownish birds chasing around, edging up to each other and then whacking each other ferociously with their wings. By their size and coloring she thought they might be kestrels, which are raptors and therefore more likely to act aggressively. But after studying the video, I thought I caught a glimpse of a white wing patch. When I looked online, I was surprised to find several Zenaida Dove male combat videos. Who knew? 

 

The name ‘Zenaida’ actually has a slight link to a very combative historical figure - Emperor Napoleon. His nephew, Charles Lucien Bonaparte, was a naturalist and ornithologist who married his first cousin, Zenaida Bonaparte, and named these doves for her. The name is used not only to identify this particular Caribbean dove species but also for a broader genus that includes White-winged Doves and Mourning Doves. In Greek, Zenaida means (roughly) ‘related to Zeus’, the supreme god in ancient Greece, and it seems to be a popular girl’s name in a number of cultures.   

 

After all the fighting and breeding is over, the dove couples are said to mate for life. They are also reported to be monogamous, though I’m not sure how closely they are monitored. You do often see them together, mostly walking around on the ground looking for seeds and insects. 

 

You might also find them perched right next to each other. Other times you might hear them calling back and forth from different trees.

 

Male and female Zenaida Doves are devoted mates

 

In our yard, the Zenaida Doves can sometimes be seen foraging with other similar, but much smaller, doves. These are not babies but Common Ground Doves, which are members of a subspecies only found in Puerto Rico and the Virgin Islands (Columbina passerina portoricensis).

 

Zenaida Doves are much larger than Common Ground Doves

 

When they do have babies, the Zenaida Doves make their nests in trees to provide some safety from potential predators on the ground (like rats, mongooses and outdoor cats). Local bird expert Laurel Brannick told me that she sometimes finds Zenaida Dove hatchlings that have fallen out of their nests (more often than other birds), and will try to put them back in the nests to protect them. 

 

Zenaida Doves nest in the crooks of trees

 

In addition to predation, many birds are also challenged by human-related habitat loss and climate change. Zenaida Doves, like other seed and insect eaters, can easily become food-insecure during hurricanes, droughts and other calamities. In general, planting native trees and shrubs will support local birds and wildlife and, in times of crisis, providing bird seed for the doves can be helpful.

 

But in many places people pose direct threats to doves. Mourning Doves are widely hunted in the northern hemisphere during the fall, mostly for sport now, though sometimes for food. Zenaida Doves can also be hunted legally in certain Caribbean islands, including Puerto Rico. So it would not be surprising if these doves do, in fact, sing rather mournful songs.  

 

Black Mampoo Trees Attract Local Birds, Wasps and Pollinators

  

A Pearly-eyed Thrasher eating an unripe Black Mampoo fruit

Although Black Mampoos are among the most common native trees in the Virgin Islands, they  tend to blend into the wooded areas and are not usually noticeable until the summer, when they produce flowers and fruit. And even then, they are certainly not flamboyant. Nevertheless they are attractive to a variety of local creatures.  

 

These are relatively tall trees, 30 to 40 feet high, often with one straight trunk that doesn’t start branching until fairly high off the ground. 

Black Mampoo tree

 

 

Their fragrant flowers start out as small buds at the ends of high branches. 

 

A Smoothed-billed Ani in a Black Mampoo tree

 

Soon the buds open up into tiny yellow cups with white, wispy stamens sticking out. The flowers are not bright and showy, but their smell seems to be attractive to a variety of insects.  

 

      

When the fruits first come out, they are light green. Then after a while they start to turn reddish purple.  

 

 

And when they are fully ripe, the fruits are very dark purple.

 

 

One interesting characteristic of the Black Mampoo trees is that their leaves tend to have strange growths on them, like little dark balls. These growths are called galls. They are caused by a type of very small wasp in the Cynipid family that has developed a parasitic relationship with this tree. These wasps deposit their eggs on the leaves, which is irritating and stimulates them to grow new defensive tissue, which then forms the round, brown galls that serve to surround and protect the wasp eggs. When the eggs hatch, the larvae eat the tissue inside the galls until they are fully grown, and then exit out of tiny holes in the galls.    

 

 

Although these galls look unpleasant, they don’t seem to do much damage to the trees. Still, growing the galls uses up some of the trees’ energy without any obvious benefit. That sounds annoying, ‘galling’, in fact. 

 

Just so you know, there is another, very different native Virgin Islands tree that is also called ‘mampoo’ -  the Water Mampoo. These trees are much larger and quite dramatic, with thick exposed roots, pale ghostly bark, and several spongy, plump trunks that spread out quickly from the base. They are found in drier forest areas, and their absorbent trunks allow them to store water, which helps them survive in times of drought.  

 

Water Mampoo tree

 

The Water Mampoo leaves are more rounded and (unlike the Black Mampoo) there are male and female forms. The female ones produce clusters of small, sticky fruits. 

 

I noticed that these two types of trees don’t seem to have a lot in common, so I wondered why they are both called ‘mampoo’.

 

There is an alternative spelling in some places - ‘mapou’- particularly in the islands colonized by the French. The Black Mampoo (Latin name Guapira fragrans) is called ‘mapou blanc’ in St. Lucia, and the Water Mampoo (Pisonia subcordata) is called ‘mapou gris’. Blanc means white in French and gris means gray. But ‘mapou’ is not a French word that can be translated. 

One source from St. Lucia identifies ‘mapou’ as an Amerindian word, another from Haiti suggests it comes from Africa. 

 

Possibly ‘mapou’ or ‘mampoo’ became used around the Caribbean to refer to certain trees with historical and cultural significance that is not adequately captured in scientific Latin names or other more recent classifications. 

 

Why Do Laughing Gulls Come to the Virgin Islands for the Summer?

An adult laughing gull has a black hood during breeding season. 

There are no gulls in the Virgin Islands during the winter, but then the laughing gulls suddenly arrive right around the first of April. And like other spring visitors, they tend to come in groups and enjoy loud, amorous beach parties.  

Laughing gull couples use buoys for offshore trysts. 

However the laughing gulls are known to be monogamous. Before long the couples will work together to make nests and raise their chicks out on the smaller, uninhabited cays. They usually stay together in large groups through the nesting season, for safety in numbers.    

I recently began to wonder where these laughing gulls actually come from, and why they are only around in the summer.  

 

Most migratory birds in the Virgin Islands arrive when it is winter in the northeast and food is scarce. Then they leave in the spring to go up north for their breeding season. In the fall, when it gets cold again in the northern parts of the U.S., those birds fly back down. 

 

These laughing gulls are on an opposite schedule – coming to the Virgin Islands to nest, and then leaving in the fall. 

 

One possible explanation could be that the Virgin Islands laughing gulls come to escape the winter in South America, where the seasons are reversed. However, the non-breeding range for these birds is mostly along the northern coasts of South America, and the Caribbean. The  seasonal temperature difference between these areas and the Virgin Islands would be fairly low. Meanwhile, they are considered to be year-round residents within some of the coastal areas of the Greater Antilles. 

 

So I am now thinking that the laughing gulls arriving yearly in the Virgin Islands have not actually traveled very far. And that they probably come for the relative safety provided by the smaller, uninhabited islands here, rather than for the warm summer weather. They may even be returning to the places where they were born and raised. 

 

The laughing gull nests are usually simple grassy structures set into low vegetation on the ground, so being isolated offshore could provide important protection from possible predators.   

 

In the summer, there are often large bunches of baby fish available around the Virgin Islands to feed hungry gulls, and their chicks. And these days, there are rafts of sargassum to pick over too. 

Groups of laughing gulls gather to dive for newly hatched fish.

Besides diving for fish (or trying to steal them from the pelicans), the laughing gulls will also walk along beaches and shorelines looking for shellfish, crabs and large insects. On popular beaches, they may also be attracted to trash left by humans. 

 

Beach walks sometimes reveal tasty crustaceans.

 

Interestingly, for the last couple of years there have been some laughing gulls staying in the Virgin Islands later in the fall than usual, including a few sightings recorded in the annual December bird counts on St. John. 

 

However, they look quite different when they are not in their breeding plumage. The black hoods become just blurry gray patches on their heads. 

 

Laughing Gulls lose their black hoods after breeding season is over. 

It takes about three years for the young ones to get their adult feathers. At first their back feathers are brown with white edges. Over time the feathers on top start turning gray.  

 

Immature laughing gulls have a mottled brown and gray look.

   

Unfortunately, large numbers of laughing gulls and other birds on islands or coastal areas near airports can sometimes be dangerous to air traffic, so air traffic controllers are not happy to see them around. In fact, just recently, a bird strike caused injuries to passengers on a small plane coming into St. Thomas. 

 

In the Virgin Islands, the U.S. Department of Agriculture’s Wildlife Services program is responsible for keeping birds from getting in the way of arriving or departing planes. Their researchers have found that patches of water collecting on the runways can attract thirsty gulls, so good drainage is important. Controlling insects so they don’t hatch in large groups on grassy areas near runways will also keep the gulls from congregating near the airport, which helps both visiting birds and people in planes stay safe.  

 

However, most of the laughing gulls aren’t all that interested in hanging around the airport. Like other visitors, I think they come to the Virgin Islands to enjoy the beautiful beaches.