When those loving instincts leave you dangling

This was not a planned blog, but I recently observed something that simultaneously intrigued, amazed and astounded me, so I wanted to share it with those of you who may not have witnessed this either.

Like many gardens in my neighborhood, my yard has its fair share of leopard slugs (Limax maximus), but they don’t bother me as they do some other people who complain about them eating their vegetables. Until recently, I never thought about the slugs much and certainly didn’t wonder about their life cycle. Then my friend Mary posted a lovely photo of two intertwined leopard slugs mating and my interest and curiosity were piqued.

A few days later, a fellow nature lover, Ace, reported that he had a cool photo to show me – and there on his iPhone was a photo of mating leopard slugs. It turns out that their anatomy makes for a somewhat bizarre spectacle – at least to a human being if not a fellow slug. Now I really wanted to see this phenomenon, too, and I followed Ace’s recommendation, going out into my yard at night with a flashlight to see if I could find some amorous mollusks. Lo and behold – as I rounded the corner of my house, there were three pairs of large slugs getting ready to reproduce! They were leaving glistening slime trails on the brick wall as they slowly got into position.

The slime that the slugs exude has multiple purposes – they can leave a trail behind them as a signpost to the way home, they can numb the mouth of a potential predator with the mucus as a means of defense, and they can broadcast their interest in some reproductive behavior by emitting pheromones to attract a potential mate.

They don’t actually need to mate to reproduce – each slug is a hermaphrodite and can fertilize its own eggs with no need of outside assistance. Slugs have an organ called a spermoviduct (SO), which has two parts – one for the sperm (vas deferens, VD) and one for the ova (oviduct, OV), as seen as this drawing from the Wikipedia page.

Some slugs apparently like reproductive acrobatics, however, and seek out a partner. The mating begins with a pair of slugs following one another around and nudging and licking one another. (A couple photos look browner – I took those with a flash but most were taken with one hand holding a small camera and the other shining a flashlight near the slugs.)

 

They then begin to curl up together and suspend themselves from a long mucus rope, which is somewhat stronger than the slime that they usually exude. They form a kind of writhing ball as they intertwine their elongated bodies (see this video for an example).

Next comes the awesomely weird part – out of a gonopore on the right side of their heads (the elongated tentacles are for vision) come their translucent mating organs (penises)! This video, which is shown in a horizontal position, lets you see how this happens.

Wouldn’t this interesting anatomy and reproductive behavior make an interesting plotline for an SF novel about a genderless society?

 

      

Because the slugs are hanging upside down, gravity helps pull down their reproductive organs, which are pumped full of body fluids until they are as long as the slugs’ entire bodies! Their penises are everted (turned inside out) and the two mollusks intertwine these just like their bodies. They take a while to exchange spermatophores as the penises twirl, intertwine, elongate and pull back to look a bit like a chandelier.

  

When the creatures have been joined at the neck for some time, they begin to slowly withdraw their reproductive organs, which are now carrying genes from another parent.

              

After they separate, one of the pair usually consumes the mucus rope from which they dangled in love as it carries extra nutrients which they can use after their vigorous efforts.

          

 

 

Each slug may spend some time examining its gonopore (above) – and perhaps they are helping push back in the penis when they do this, too. After watching the process for two pairs of slugs, I decided to give the third pair some privacy during their mating tryst. On the wall beneath my screened porch, I discovered another slug with a mucus rope dangling from its tail – leaving me with a little mystery as to why this might have happened. A partner slug was not in evidence except for a much smaller slug – perhaps the big one tried to mate but the younger one was not ready. These mollusks with a life span of 2.5-3 years don’t become sexually mature until they are 2 years old.

    

I do know that at least three and perhaps six slugs will each be laying up to 200 eggs somewhere in the yard. And when I see them in the future, I will undoubtedly always be picturing them in my head doing their dangling dance with intertwined translucent blue tubes that will help promote their future generations. My discovery of their life cycle has also reinforced my support for scientist Hope Jahren’s (Lab Girl) observation: “…being able to derive happiness from discovery is a recipe for a beautiful life.”

Costa Rican rambles 6B – On the road

After leaving Los Cusingos, we continued our Costa Rican trip by birding along roads, where we saw more of the countryside, including the ubiquitous cecropia trees with their beautiful leaves. We had heard that some of the banana plantations had become diseased and were replaced with sugar cane; this apparently happened in the 1950s when a fungal disease, Fusarium wilt, affected banana crops. Bananas are still a major crop and many small homesteads along the road had a banana tree in the yard. And these fruits were very popular at the bird feeders.

The day before, we had seen sugar cane growing in various places; the varieties in this country are tall perennial grasses. Farmers were cutting some down with machetes in various places as we traveled and we saw trucks and tractors laden with the crop going to processing plants.

 

  

These plants were right beside the roads we drove along.

 

In one area, we crossed a fairly dry river with the remains of a twisted metal bridge on one of its banks – apparently, the result of Tropical Storm Nate which left the country with several fatalities and lots of destruction in October 2017.

We stopped for lunch at an open-air restaurant with signs advising that both sexual harassment at school and in the workplace, as well as smoking, were forbidden. We could see birds flying by in a valley overlooked by the restaurant veranda, which was a nice touch.

A fair amount of time was spent looking at shorebirds enjoying the water at the San Isidro sewage lagoons. This was not my favorite spot – it didn’t smell bad but the lighting was awful, the birds were far away behind fences that I couldn’t photograph over or through very well. I did manage a photo of a mangrove swallow (Tachycineta albilinea) zipping over the water in the distance. The photo of the variable seedeater (Sporophila aurita) was in dense shrubs and then I over-compensated – but you can see the male is black with a white mark at the neck and the females are brown.

    

A great kiskadee (Pitangus sulphuratus) perched in a tree and on a wire not too far away.

 

A green-breasted mango hummingbird (Anthracothorax prevostii) perched, too.

  

At another roadside stop, I spotted a nice dog who was resting in a hole in the bank of a creek. At first, I thought he was clever to find a cool spot but then I felt badly for him when I saw he was chained.

 

A restaurant at one stop turned out to be older than me, which was a nice observation.

The roadside birding was often on a hilly road and we could see villages below.

 

 

In the dense foliage, we saw a dark-capped flycatcher (a very small bird, Empidonax atriceps) sharing a shrub with a euphonia. The yellow-thighed finch (Pselliophorus tibialis) fortunately came out in the open – this bird became one of my favorites.

 

 

 

 

My photo of the long-tailed silky flycatcher didn’t turn out well and I got a better photo later; this was compensated for me by the sooty thrush (Turdus nigrescens), who posed nicely for a long time on a lichen-laden branch. That was a nice way to end the day as we made the last miles to our next hotel for two nights, the Sueños del Bosque cabins where the bathroom was decorated with flowers on the toilet seat, sink drain and shelves. Next instalment coming soon!

 

Costa Rican rambles 6A – Los Cusingos

Finally, back to Costa Rica (in memory)! The past couple months were very busy and often stressful for me, so it is so very nice to again look back to the wonderful days we had looking for Central American birds (and other wildlife) in Costa Rica. On the fourth day of our 9-day trip, we moved to another hotel for a couple nights, stopping several times along the way to bird along roads. The photos from this day were not that great, but they do provide an impression of what we were seeing.

Before we left, we birded the grounds of the hotel where we had spent the night. There were some pretty flowers and a white-crested coquette hummingbird (Lophornis adorabilis), as well as a rather large long-horned borer beetle (perhaps Callipogon barbatus species, but that’s not certain).

We spent some time peering into a rather dark and dense brushy area, looking for uncommon wrens. I was able to photograph a rufous-breasted wren (Pheugopedius rutilus) with some difficulty. Then, just before boarding our bus, a yellow-headed caracara (Milvago chimachima) perched in a nearby tree, giving us some nice views.

  

Our first stop, however, was a park called Los Cusingos, which is a property formerly owned by US botanist Alexander Skutch. He lived there for 63 years until his death at the age of 99 years. While Skutch earned an income collecting plants for museums, his passion was birds and he wrote more than 40 books and 200 papers on ornithonology.

  

Now his former home is part of a bird sanctuary run by the Tropical Science Center and you can see a variety of birds, like this buff-throated saltator (Saltator maximus) and the yellow-olive flycatcher (Tolmomyias sulphurescens).

        

The staff had put out fruit on a feeding station to attract birds and this brought in several, including a female Cherrie’s tanager (Ramphocelus costaricensis) and a golden-hooded tanager (Tangara larvata).

     

The station was also very attractive to a red-tailed squirrel (Sciurus granatensis), who was not in the least perturbed by our presence nearby.

We set off onto the trails in search of new avian species but also had time to admire many types of trees and plants, which I still must identify. Some had very sharp spines.

The dense foliage with a little sun creating dappled views made photography a challenge for me. But I did get a couple photos of a little bird called the plain xenops (Xenops minutus).

As we hiked, a few beautiful butterflies appeared; the one with orange spots was, I believe, a crimson patch (Chlosyne janais) and the other was a zebra-striped hairstreak (Panthiades bathildis).

A chestnut-sided warbler (Setophaga pensylvanica), familiar to me from North Carolina, put in an appearance and a lovely little lesser greenlet (Hylophilus decurtatus) peered out from some large leaves.

A summer tanager (Piranga rubra), which I’ve been lucky to have in my own yard, was a pleasure to see, as was a spot-crowned euphonia (Euphonia imitans).

  

One of my favorite birds, of which I unfortunately had blurry photos, was the entertaining red-capped manakin (Ceratopipra mentalis). He stayed very high in the canopy and was sometimes behind leaves but, when he emerged, he did a great sideways moonwalk back and forth on the branch, which was part of his courtship behavior. What a very cool sighting!

   

Back near the entrance to the reserve, there were some lovely orchids and a brilliant green honeycreeper (Chlorophanes spiza) to see us off as we set off on the road – to be continued in the next blog!

  

Avian generations in the making – part 1: courtship

The tragedies being faced in the Caribbean islands after hurricanes Maria, Jose and Irma are horrible and other than donate cash to help alleviate the needs, I’m not in a position to offer more assistance. I’m grateful for all those who can and hope government assistance will be forthcoming to help all the people in those nations recover.
The effects of the hurricanes also will be noticeable for the wildlife. Many of those living on land will drown or die of hunger; some birds may be a little luckier – able to shelter against the winds if they are native to a place or able to change their migratory pattern (e.g., delay arrival on wintering grounds) for a time. But when the effects of the storms are immense with lots of habitat destruction, the birds, too, will lack places to shelter and not have sufficient food supplies to survive.

It’s thought that some birds endemic to the islands may be severely endangered as a species. On 22 September, birders were happy to hear that eight Barbuda warblers (Setophaga subita) had been spotted on that island; not a lot but they may help ensure this tiny bird doesn’t become extinct.  At the time of writing this blog, the fate of some other bird species was still unknown. I hope that all the Caribbean bird species survive and will be thinking of them as I share this series with you on how birds take measures to ensure future generations. (It might seem odd to write this series now, but some birds are still feeding their young here.)

So, the process begins with courtship. Some birds mate for life, or at least form long-term (multiple-year) bonded relationships. They include bald eagles, black vultures, blue jays, Canada geese, white-breasted nuthatches, brown-headed nuthatches, Northern cardinals, Carolina chickadees, American crows, pileated woodpeckers and my favorite raptor shown above, the osprey (Pandion haliaetus).

Those who form ongoing bonds may have a courtship period that consists of the male bringing the female some food to indicate it’s time to get ready for nest-building. This was the case for these lovely Northern cardinals (Cardinalis cardinalis).

The American crow (Corvus brachyrhynchos) has a similar behavior; in my yard, I sometimes throw out bits of apple or bread for them in the spring as these seem to be considered real treats. The female will sit on a branch overhead calling until the male brings her some – and sometimes almost shoves it down her throat!

The Northern mockingbird (Mimus polyglottos) males will sing their repertoire in the spring to entice female mates – often they perch on the top of trees and fly up and down with spread wings in a beautiful display while singing.

        

   

The yellow-billed cuckoo (Coccyzus americanus) seeks new mates each year but has an interesting courtship behavior described by All About Birds: “A receptive female perches with its head up, pumping its tail slowly up and down…Just prior to mating, the male Yellow-Billed Cuckoo snaps off a short twig that he presents to the female as he perches on her back and leans over her shoulder. Both birds then grasp the twig as they copulate.”

 

     

 

The downy woodpecker (Picoides pubescens) females and males may both flutter between trees with slow wingbeats. Two females may also compete for the attention of a single male, a behavior I observed this past spring and which surprised me.

 

     

The male brown-headed cowbird (Molothrus ater) will vocalize for the female while spreading his wings in a display.

The killdeer (Charadrius vociferus) has a somewhat prettier courtship dance, bending forward and spreading its tail feathers to show off the colorful underside.

  

Next year, I hope to see more of the birds courting as it gives me a happy feeling.

The next step for the birds is nest-building. We don’t have the bowerbirds in North Carolina, who build elaborate nests as part of their courtship. But the species we have do spend a good deal of time on their nests and I’ll share some of their efforts in the next part of the series. (But one or two blogs on another topic will come first.)

 

Credit map: By Kmusser (Own work, all data from Vector Map.) [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)%5D, via Wikimedia Commons

The beautiful “baker” bird

Recently, I’ve had the good fortune to observe a small bird at close quarters that I had only seen in a couple glimpses in the past, the ovenbird (Seiurus aurocapilla). Like the ruby-crowned and golden-crowned kinglets, this little avian also has a stripe atop its head. Like the golden-crowned kinglet, the stripe is always visible and orange in color, blending in nicely with its other muted brownish and cream colors.

 

The ovenbird gets its name from the shape of its nest, which is built on the ground in a shape reminiscent of an outdoor or Hopi oven. It is domed and has a side entrance and can be difficult to see.

The ovenbirds spend the winters in the Caribbean region and Central America and then come North for the summer breeding season. My sightings of the singing male have been at our local nature reserve, Mason Farm Biological Reserve, where I volunteer as an invasive plant eradicator and sometime planter of native flowers.

 

The male sings a three- to-five note call in the spring as part of his courting behavior and the call varies among individuals. When males are in neighboring territories, they will sing together in duets and it can be difficult to know how many birds are singing.

   

The sound is so loud that you expect to see a much larger bird and his song inspired poet Robert Frost to dedicate a poem to him.

 

If he is sitting on a branch, you can eventually find him but it can be a challenge since they prefer to reside in forests with heavy canopy cover so that it is fairly dark.

 

   

Once you see him, you may be able to watch for a while as they don’t seem to be very wary of people. This individual let me observe as he groomed on a low tree branch, pausing now and again to let out a few notes.

  

   

These birds prefer areas with heavy leaf litter for their homes – the leaves provide cover for their ground nests and they blend in really, really well as they scurry about foraging in the leaves for insects, worms and snails to eat. Both the females and males participate in feeding the fledglings until they can fly at about 30 days.

When they emerge into a patch with a bit of sunlight filtering down through the leaves overhead, you have a bit better chance to see them. Otherwise, you may end up staring at ground cover until you catch a bit of movement and can zero in on the motion to see them.

 

Photographing the bird is a challenge since they spend their time in areas with so little direct light. My first photos were a bit dark, but then I increased the ISO on my camera considerably (a tip from fellow photographer, Mary – thanks!) and the photos were a bit better. Still, the somewhat darker photos reflect the environment in which you discover these little troubadour warblers. Now that I know where to look for them, I hope to see them more often in years to come.