Tag Archives: juvenile

Awesome amphibians in Costa Rica

Posted on by
4

During my two trips to Costa Rica (so far?), it was my good fortune to see different kinds of animals besides the birds which were the focus of the trips. There are a lot of interesting amphibians and reptiles to see; in this blog, we’ll see some of the amphibians that I managed to photograph. I was ultimately able to identify almost all of them except the one to the right; if anyone can tell me which frog this is, it would be appreciated!

 

One of the most famous frogs in the country is the little (0.75-1 inch) strawberry poison dart frog (Oophaga pumilio), also known as the blue jeans frog because many individuals have a bright red upper body accented by a bright blue lower half. It turns out that the species has an estimated 15-30 color variations – in 2000, totally blue individuals were seen at the La Selva Field Station.

The female lays 3-5 eggs on a leaf and the male then keeps the eggs hydrated with water he transports in his cloaca. After the eggs hatch and tadpoles emerge, the female frog transports them on her back and deposits each one separately in a small pool formed in the crevice or hole of a tree or a large bromeliad. There, the tadpoles consume only unfertilized eggs that their mother feeds, a practice called obligatory oophagy,

 

The feeding habits of the adults (certain ant and mite species) are what makes them poisonous when touched or eaten. Their skin is toxic and humans should wash their hands vigorously after touching them.

A very tiny frog that we saw last year was the common tink frog (also called dink frog; Diasporus diastema). I’m not absolutely certain that the two shown below are tink frogs but think they are. These tiny frogs change color, having grayish brown skin with spots or bars during the day and a pale tan or pink color at night, when it is most active.

 

 

A somewhat larger amphibian that we saw at the same pond as the tink was the hourglass tree frog (Dendropsophus ebraccatus). Part of the species name comes from the Latin term ebraccata, which means “without trousers”. Some people call this frog the “pantless frog” because they think the smooth yellow thighs that contrast with its highly patterned back make it look as if it is not wearing pants. These individuals had patterns on their thighs, however!

The attractive hourglass frogs were in an amorous mood when we spotted them. The female chooses her mate and he mounts her to deposit his sperm. She then will seek out a suitable place for her eggs, either in the water or a leaf overhanging water. When the arboreal eggs hatch, the tadpoles roll off the leaf into the water below.

These frogs are of interest to scientists because their skin contains bioactive peptides which have anti-fungal and anti-bacterial properties and might even have therapeutic properties useful in treating diabetes.

 

The pond had quite a few frogs in residence and several brilliant forest frogs (Lithobates warszewitschii)were among them. They are slender-looking frogs with pointy heads. Their sides are apparently always darker in color than their backs.

 

 

Their coloring seems to vary somewhat, being browner in some individuals and featuring more green highlights in others. They tend to have yellow spots on their legs.

They do not have vocal sacs or slits but do make trilling sounds.

 

 

We were lucky to catch a glimpse of a red-eyed tree frog (Agalychnis callidryas) at the pond. Although some lodges will ask you to avoid using a flashlight during night-time walks to see amphibians, it’s very difficult to spot them without some use of a light. That’s how we managed to spot the tree frog.

We came across the Canal Zone tree frog (Boana rufitela) taking a daytime nap, right out in the open on a large leaf next to a walking path. This frog is also known as the red-webbed or scarlet-webbed treefrog. It used to have the scientific name Hypsiboas rufitelus, which was changed for a reason I couldn’t determine.

The smoky jungle frog (Leptodactylus pentadactylus) is Costa Rica’s largest frog species; males grow to as much as 7.3 inches (18.5 cm). The adults are so big that they can eat small mammals (e.g., bats), small birds and lizards. They have some interesting characteristics. In contrast to the little blue jeans frogs, who only lay 5 or fewer eggs, female smoky jungle frogs lay about 1000 eggs at a time! They can secrete copious amounts of mucus, which makes them difficult to hold for predators; in addition, these secretions are toxic. They can even vaporize the toxin, causing people to sneeze and get swollen eyes.

What has further contributed to making them famous is the alarm call that they emit when captured; some liken it to a human person screaming. It doesn’t sound like that to me; rather, what I heard in a video sounds to me like a sound that a distressed cat might make.

That brings us to Costa Rica’s largest amphibian, the cane toad, also known as the marine toad. They are not only this Central American’s biggest amphibian, though; they are the largest toad in the world, growing as long as 9 inches long (22.86 cm) and weighing up to 3.5 lbs (1.59 kg).

This animal has also gotten a new scientific name; while it used to be called the Bufo marinus, it is now known as the Rhinella marina. Like some of the frogs, this toad has toxic skin and they are especially dangerous for dogs.

They were introduced to different countries to control pests as they have voracious appetites. Now they are considered an invasive species and pests themselves.

In 2018, I came across these toads in different places. There are a few living around a fountain in the hotel in San José where our tour groups stayed; they enjoy taking a shower under the running water.

To end today’s offering, I’ll show you the frog that really fascinated me most — the reticulated glass frog (Hyalinobatrachium valerioi). Our guide, Cope (who showed us the awesome spectacled owls and bats shown in previous blogs), led us to this awesome amphibian. It has a green and yellow back but its ventral (abdominal) skin is completely transparent! The frog’s heart is covered by white tissue and its liver and digestive tract are also white. Here you see the male frog on a leaf guarding eggs – he actually looks pretty much like the egg masses!

Isn’t nature endlessly interesting? Next blog: Costa Rican reptiles!

Local beauties in the woodpecker family

Posted on by
10

My first blog on this website, written in October 2013, focused on woodpeckers; my first blog of 2020 was also about these birds (I know, the blog prior to that says 1 January but I posted it on 31 December; WordPress time is ahead of mine. 😊) Obviously, they are one of the bird species that I enjoy watching so to follow up my last blog, I’d like to share just a few more photos of three species that it’s my privilege to see locally. They are quite different from one another in appearance but equally beautiful and it’s always a delight to see them. (And no, it’s not snowing where I am; this is a photo from January 2018; we are supposed to have 70⁰ F/21⁰ C in a couple days!)

The Northern flicker (Colaptes auratus) is found in the Western hemisphere and looks quite different from many other woodpecker species. In the US, there are two sub-species. In the West, there is the red-shafted and in the East the yellow-shafted variant. The “shaft” refers to the undertail feathers. When the bird flies, however, you can also see the beautiful, otherwise hidden, yellow hues on the underside of other feathers.

 

Those yellow feathers also come into view when the flicker is upset, like this one was with a brown thrasher who came to the feeder pole where it was taking a brief rest. (This is pretty unusual; they don’t come to the feeders often.)

The flickers have some interesting distinguishing features: they are one of the few woodpeckers that migrate; they are the only woodpeckers that primarily searches for food on the ground, rather than in trees; and they probably eat more ants than any other North American bird!

And, depending on the weather (overcast, cloudy but light, sunlight), their coloring can look different – this is not only because the photos were with different cameras).

 

They also eat berries and seeds in the autumn and winter.

 

Like other birds, the flickers do nest in tree cavities.

 

You can distinguish males from females by the black moustache stripe, which the females lack.

 

 

The yellow-bellied sapsuckers (Sphyrapicus varius) is a woodpecker that can blend in quite well with the trees on which it seeks its food. Their mottled feather coloring often provides a good camouflage and you might not see one if it is sitting still.

The males have red crowns and red throats; the females have a white throat and the juvenile birds lack the reddish hues.

 

 

 

These woodpeckers may be followed around by other birds. For example, last year I saw ruby-crowned kinglets following sapsuckers at one reserve. Why would they do this? It’s because the sapsuckers drill shallow holes into trees which will then ooze out sap on which the woodpeckers and other birds feed. And the kinglets will find insects around the sweet sap. (At a children’s workshop on trees that I conducted last fall, one young boy asked me if humans could also drink the sap from their holes. I hadn’t researched that but answered that perhaps we would like the sap from a maple tree but not from an oak.)

 

The sapsuckers eat insects, berries and fruit like other birds.

 

Last in my line-up of local woodpeckers is the red-headed woodpecker (Melanerpes erythrocephalus). The adult males and females look alike but adults and immature birds look very different indeed. While the mature birds are characterized by a deep red head, solid black back and white rump and belly, the juvenile and immature youngsters have brownish heads and bodies and black and brown striped rumps.

 

 

When they are transitioning to adult plumage, they will have mottled red heads and begin losing the brownish hues.

 

They have one of the most identifiable (for me) calls of the woodpeckers. Listen to this recording (Arkansas, 22 March 2005); it almost has a warbling quality to my ear, which many websites describe as a “churring” sound.

I’ve been lucky lately as there is an immature red-head reliably patrolling a certain territory in a forest that I visit so that I can be fairly certain of always seeing her/him sooner or later. This is a boisterous bird who loves to call and make its presence well known.

S/he doesn’t peck too loudly but if some vigorous drilling is required, this bird is up to the task. They have sturdy and powerful spike-like bills. The woodpecker beaks have three layers: the rhamphotheca (outer layer) is made of keratin; the middle layer is porous bone and the inner layer is made of mineralized collagen and contains a large cavity. The tongue bone (hyoid) winds around the bird’s skull and functions like a safety belt that helps cushion the brain when they are engaged in high-velocity and impact drumming and drilling. On the whole, however, these woodpeckers tend to drill less but fly out often into the air to catch insects on the wing.

They eat insects, fruit, berries, eggs of other birds but also really enjoy nuts, especially acorns and beechnuts. They make stashes of nuts in tree cavities, crevices and under bark for later consumption.

When depositing or withdrawing from holes in trees, they will use their tails like other woodpeckers to help them balance as they perch.

 

A surprise for me was that they also occasionally eat cambium and tree bark.

 

If climate change continues and results in an overall warming trend of plus 2 degrees, these birds could lose up to 64% of their range. Yet another reason to do what we can to decrease our energy consumption and advocate for policies and regulations to reduce global warming due to human actions.

 

One more interesting note about woodpeckers (for the time being): did you know that there are no woodpeckers (including flickers and sapsuckers) in the polar regions, Australia, New Zealand, New Guinea and Madagascar?

 

I’ll end with a quote from an interesting book that I am currently reading. The author, Robert Macfarlane, describes research into the “wood wide web” and then muses on what it could mean for humans:

 

“If there is human meaning to be made of the wood wide web, it is surely that what might save us as we move forwards into the precarious, unsettled centuries ahead is collaboration: mutualism, symbiosis, the inclusive human work of collective decision-making extended to more-than-human communities.” (Underland; my emphasis)

 

Quebec chronicles – the marine mammals, part 2

Posted on by
5

Our whale-watching tour set off from a dock in the village of Tadoussac. A naturalist was on board, but she stood only at the front of the boat and her electronically-enhanced voice was difficult to understand with some static and heavy winds interfering. Our group stationed itself at the back of the boat so we would have unobstructed views of the birds and any possible whales. To our enormous delight, a fellow passenger called out a view of the first whale to swim near – a minke whale (Balaenoptera acutorostrata), which is a type of baleen whale.

illustration credit: International Whaling Commission; https://wwhandbook.iwc.int/en/species/minke-whale

These smaller whales, which feed on krill and smaller schooling fish, are known for frequently breaching but that didn’t happen during our tour. It was cool to see this one swimming along though. We are unsure if we saw it again as they appeared somewhat similar to the fin whales, but the other whales we saw on the tour were a pair and minkes tend to be more solitary. Unfortunately, the minke is now the most numerous whale species worldwide and therefore a main target of the whaling industry.

Our next sighting way out on the river was a pair of harbor seals (Phoca vitulina), whose heads bobbed on the surface as we passed by. Then we were thrilled to see a “blow”, a whale spouting water into the air.

A pair of fin whales (Balaenoptera physalus) was swimming around in our vicinity and though they did not breach, they did rise to the surface multiple times – once quite close to our boat.

Illustration credit: International Whaling Commission; https://wwhandbook.iwc.int/en/species/fin-whale

These whales, considered an endangered species, are the second largest mammals in the world and have been nicknamed the greyhounds of the sea because of their swimming speed.

They have sleek bodies that can grow to 80 feet in length. Sometimes, you could spot where they might partly surface due to a bit of turbulence in the water.

Their diet consists of krill, crustaceans and small schooling fish. If they get enough to eat, can avoid predators (e.g., orcas) and man-made threats, they can live to be 100 or more years old! (The minke whales live 30-60 years.)

A scientific group has been collecting photo IDs of fin whales since 1986; they now have some 100 identified individuals who have received names such as Capitaine Crochet, Triangle, Caïman and Zipper. Another group has a catalogue that has identified 450 fin whales since 1980.

While we were thrilled to have seen the minke and fin whales, a beluga sighting remained a wish. That evening after the boat trip, Chloe and I were talking about whales as we gazed out at the St. Lawrence Seaway from the balcony of our rental house. I was of the opinion that if we really made it our intention to see a beluga, we would (Illusions is one of my very favorite books!). Fleeta joined us a little later on the balcony and then excitedly called out – “Beluga!!!”

Everyone came running out from inside the house and a few of us ran for cameras, despite the fact that all we could really see was a white splotch against the blue water. Those with binoculars likely had a much better view, but I didn’t care – we had our elusive sighting! The following photos, taken on our last evening and the next morning when it was raining, are admittedly not good ones but do give you an idea of what we saw.

The beluga (Delphinapterus leucas) is the only white whale and is known as the canary of the sea for its broad range of vocalizations. This trait, combined with the species’ curiosity which causes it to surface near boats to look at humans, unfortunately has led to it being one of the aquatic mammals that are hunted and captured (and sometimes bred) for the entertainment industry.

In contrast to the fin and minke whales, the belugas are social mammals, often traveling in groups and also moving from one group to another. On our last evening in St. Irénée, we probably saw about 12-15 of them! If you look closely at the white spots, you will see there were seven in this photo.

Males tend to associate with other males and females and their calves (born about every three years) hang out together. The young belugas are born gray and turn white between 5-12 years. Another interesting fact is that these whales molt in the summertime!

The St. Lawrence Seaway belugas, the southernmost beluga population in the world, are protected under Canada’s Species at Risk Act. This became necessary to multiple threats, a main one being massive hunting of the species. From 1880 to 1950, about 15,000 of these whales were killed, being blamed as “white demons” for threatening commercial fishing (which proved to be false). The latest estimate of how many now remain in this area is a paltry 889 individuals.

Hunting of belugas was outlawed in Canada in 1979 but other threats to the species persist. Besides chemical and plastics pollution, they succumb to getting hit by boats, being ensnared in fishing nets, and falling prey to predators (e.g., orcas). They may also be facing competition for their food sources, including the sardine-like capelin fish; here you see a couple that washed ashore.

 

Wildlife conservationists have been alarmed by a large number of female and baby belugas washing up on shore along the Seaway since 2008. Many of the mothers have died in the neonatal period and researchers are asking whether the mammals are lacking sufficient energy and failing to find sufficient food.

It is thought that the Seaway habitat may be changing with damming of rivers that flow into it. Noise pollution from whale-watching, boating, military sonar, oil and gas drilling may also be making life difficult for the whales as it disrupts their navigation. On the day we went out, a couple zodiacs zoomed a bit close to a pair of fin whales, even though they are supposed to observe the same distance rules as the larger boats. Hopefully, the authorities will be closely monitoring this.This is now being studied by Fisheries and Oceans Canada. In 2019, the Groupe de recherche et d’éducation sur les mammifères marins (GREMM) received a grant from the Prince Albert II of Monaco Foundation to study the increased mortality among the female and young belugas.

It would be great if the Beluga Whale Health Project could discover what is harming the belugas in the Seaway since these mammals can live more than 100 years of age in favorable circumstances. That is important for the species because it was recently documented that belugas have their own cultures in groups that stay together for generations; one researcher Greg O’Corry-Crowe, commented: “”We have compelling evidence, in our view, for the evolution of culturally inherited migration knowledge and behaviour.” This also has led to the intriguing question of whether their ability to learn from one another might help them cope with changing climatic conditions.

 

Hopefully, something can be done in the shorter term to help all the whales cope with the challenges and threats facing them. Outside the whaling and marine entertainment industries, many people would like to see them survive and thrive in the wild. They inspire artists as well, as shown by the metal beluga sculptures on display down the road from where we stayed.

At the Domaine le Forget in Charlevoix, another sculpture was called the Song of the Whales by Peter Lundberg.

It was a joy to see the whales during our trip, especially given the threats to which all the aquatic mammals are subject: hunting, getting caught in fishing nets, poisoning due to toxic chemicals from litter and oil spills, and ingestion of the ever-increasing plastic trash that is floating into our oceans. I would love to return to the area in warmer weather in the hope of getting closer to the belugas to see them better. I would again go on one of the large whale-watching boats because it appears that the smaller boats might be getting too close to the marine mammals. If we want to see the cetaceans in person, we need to think about how we can do it most responsibly while protecting them. The St. Lawrence Seaway is quite beautiful and will hopefully continue to offer a home to the southernmost belugas.

Growing up barred – Part 2: personal care

Posted on by
7

The young barred owls that I observed this past summer at the Mason Farm Biological Reserve could be found rather predictably in two places at the reserve, both of which were near water. They were quite beautiful to see.

Barred owls (Strix varia) are the only owls in the Eastern USA who have brown rather than yellow eyes. When adult, barred owls have short feathers on their heads but no ear tufts. Their eyelids are also feathered. The juveniles still have fuzzy down feathers on their heads and pink, barely feathered, eyelids as you can see here.

     

Adult barred owl                                                                Young barred owlet

Their feathers extend down their legs and feet right up to their talons. The owls’ claws are less curved than other raptors’ talons which makes it possible for them to squeeze their prey to death.

  

  

As they grow, the young ones will groom often, pulling out downy feathers.

    

They frequently stretch out their wings and tails when grooming.

                    

  

Baths were also a welcome form of personal care.

  

This was especially so during our very hot summer days. The fact that I was standing about 5 feet away did not deter the owlets from enjoying vigorous dunkings in the water ditch.

 

I did not see them bathe at the same time; they appeared to take turns. Perhaps each one was keeping watch for the other one when they were vulnerable.

The siblings did indeed seem to be very aware of each other’s activities and when I observed them, they didn’t stray far from one another. The next blog will show a little of their interactions.

 

Growing up barred – Part 1: becoming independent

Posted on by
7

From the ages of about 8-19 years, I lived in a house that had a nice backyard and was not too far from some neighborhood woods with a creek. As a child, I read under backyard trees, planted a flower garden and played in the woods with friends. While I became familiar with squirrels, robins, frogs and some bugs and loved being outdoors, I didn’t spend lots of time looking for wildlife. And I never saw an owl in the wild.

Now decades later, I’ve had the good fortune to learn a good deal about various members of the wildlife community while spending time finding and watching them. And in the past couple years, I’ve been privileged to see owls up close in the wild; for example, the owl below was perched next to a pathway at dusk when I walked by a few days ago.

This past summer was unique for me, however, because I was able to observe a pair of juvenile barred owls (Strix varia) at the Mason Farm Biological Reserve as they set off on their life’s journey outside the nest. I’d like to share a bit of what I saw with you in a three-part blog. This one is about them finding their independence. The next two will focus on their grooming and interactions.

Barred owl pairs usually bond for life; if one mate dies, the survivor will seek another partner soon after. They tend 2-4 eggs, which hatch after 4 weeks’ brooding and the young leave the nest after four or five weeks. They remain dependent on their parents for food for some time after that even though they may be almost as large as the adults at 16-25 inches in length (40–63 cm); their wing span can stretch up to 3-4 feet (38-49 in, 96–125 cm).

When I first spotted the young owls in June, they could already fly. Nevertheless, they did need to find their balance occasionally as they perched and moved along branches and snags.

 

The owlets were making a keening noise the first time I saw them. At first, I didn’t recognize it, and I thought perhaps some small mammal was in distress.

Eventually, the plaintive call helped me locate them above me in a tree. This particular call apparently is used by the babies to call to their parents. I figured mom or dad was close by as the owlets kept looking upwards and eventually the parents did fly in with a meal – crayfish as far as I could tell.

 

On several occasions over the next 6 weeks or so, I would hear the owlets making that keening call and staring upwards. I figured the parents were nearby, but they were obviously just keeping an eye on their offspring and not feeding them (at least not when I was there).

It was time for the young ones to learn how to get their own meals.  Although barred owls usually hunt at dawn and dusk, the young owls were busy looking for food during the day. The mammals they eat include voles, mice, shrews, squirrels, rats, rabbits, bats, moles, opossums, mink, and weasels. Birds are also a food source and their prey may include woodpeckers, grouse, quails, jays, icterids, doves, pigeons, cardinals, cedar waxwings and grackles. They also eat amphibians, reptiles and insects (e.g., snakes, slugs, lizards, frogs and toads, salamanders, crayfish, turtles, scorpions, beetles, crickets, grasshoppers) and it was the latter group of prey animals that I saw the owlets hunting. Here for example, it appears one young owl had caught a crayfish.

One day, one of the pair was grasping a twig in its beak; I’m not sure what it was doing but it seemed to have some purpose. Perhaps it was testing how strong its beak was.

  

That a strong beak can be an asset became apparent on another occasion. One of the juvenile owls suddenly flew from one tree on the other side of a water ditch to one above my head. There was much rustling of branches and leaves and when I got into a spot where I could see the bird, it became obvious s/he had caught the largest stag beetle I had ever seen at Mason Farm Biological Reserve. It appears that the giant stag beetle (Lucanus elaphus) drinks tree sap, which must have been what it was doing when the owlet got hold of it. The problem for the owl was how to eat the beetle when those large pincers were in the way.

     

The owl would try to grab hold of a pincer but lose its grip; s/he would turn the beetle around but was having a very difficult time getting those defensive appendages off. This went on for quite a long time, which made me feel a bit sorry for the beetle.

 

Finally, the owl had success and was able to settle in for a crunchy meal.

 

They expel the indigestible parts of their prey in owl pellets that they cough up regularly. Here you see the contents of one a friend found under a favorite perching branch at the reserve.

Another day I saw one owlet suddenly fixate on the water ditch.It turned out that quite a large rat snake (Elaphe obsolete; Pantherophis alleghaniensis) was swimming by. The owl watched it carefully as it climbed out of the ditch and eventually crossed the adjacent walking path, never making a move to tackle the reptile. I had remarked on this encounter to the reserve’s land manager, who said it was probably a smart move on the owlet’s part, since the snake was large enough that it could have wrapped around the owl’s head and choked it.

The young owls seemed to have learned a lot about life as a predator as they grew older. It was fascinating watching them explore their world.

Next up: how the owlets cared for themselves.