Costa Rican mammals, part 2 – those quite different from our Carolina wildlife neighbors!

Seeing mammals that we don’t get to enjoy during nature outings in the Carolinas was one of the treats of my Costa Rican trip. Although we spotted spider monkeys during our outings, it was the mantled howler monkey (Alouatta palliata) that we saw – and heard – most often. My first sighting of one was last year, when its white scrotum identified it as a mature male.

These primates eat mostly leaves (50-75% of its food), designating its diet as folivorous (new word for me!).

This low-energy diet means that they sleep and rest a lot – all night and about 75% of the day! They will supplement their leafy meals with fruit and flowers, and they get their water from bromeliads and holes in tree trunks.

Their large hyoid bones amplify the sound coming from their vocal cords so that their calls echo up to 3 miles (5 km) throughout the forest.

Interesting fact: if the howler is disturbed or irritated by humans, it will sometimes urinate or defecate on them, having surprisingly good aim from high in the tree canopy!

Another arboreal mammal that everyone in our group found endearing was the three-toed (brown-throated) sloth (Bradypus variegatus). These animals are apparently quite popular with tourists and often appear in logos and signs. An orphaned sloth was brought to one hotel where we stayed; the staff let the youngster go up in a tree in the courtyard where we could see it.

     

I had seen (and touched) a sloth in a friend’s back yard in Bolivia once (right); seeing another one close-up outside a zoo was a new treat. I love how they move in slow motion. Their sluggish movement is a result of their diet – just like the howler monkeys, they are folivorous and conserve energy as a result of their mostly leafy diet.

 

That slow movement and the fact that they cannot walk on all fours, unfortunately can also be the cause of their undoing. Their movement on the ground consists of dragging themselves forward by their forearms and claws. Our guide told us that when they cross roadways in that position, drivers may not notice them on the pavement until it’s too late to avoid them. ☹

An interesting fact is that their rough hair eventually comes to harbor various organisms, including cockroaches, beetles, moths and algae. So picking them up and holding them is perhaps not advisable – both for the human who can get insects all over them and for the sloth, who can get upset by being held. (The sloth I touched in Bolivia, below, was at the base of a tree and when I put my hand on its chest, it made no movement but I could feel its heart rate suddenly increase rapidly, so I backed off!)

 

Another interesting behavior – once a week, the sloths leave their trees to defecate on the ground. At this time, they become vulnerable to predators. (The sloth in my friends’ yard unfortunately did this and was killed by a neighborhood dog.)

 

On the ground, a slender dark mammal that frequents hotel gardens, people’s yards and nature reserves is the white-nosed coatimundi (Nasua narica). These mammals are related to raccoons and people in Costa Rica will tell you that they are Costa Rican raccoons.

 

Coatis, as they are popularly known, travel both on the ground and in trees, although I only saw one arboreal individual. They usually spend the nights in trees and then come down to look for food, which includes small vertebrates such as mice and lizards, eggs, snakes, insects, carrion and fruit – a varied diet, for sure!

The coati below was busy at the side of a mountain road we walked; it was unclear to me what it was doing. There was obviously another animal there and at first, I thought it was a young coati, but I don’t think that was the case. I now wonder if another mammal had died and the coati was investigating it as a food source.

 

They do not appear to be very wary of humans; this one passed by fairly close in a wooded area. Apparently, people will feed coatis strawberries along roadsides, which will undoubtedly make them less wary of humans. This coati might have been a male as they are solitary except for mating season when they will join a female group for a time.

Another ground-dwelling mammal we saw on multiple occasions in different areas was the Central American agouti (Dasyprocta punctata). This rodent plays an important role in the forest as it is a seed disperser. Like squirrels, the agoutis bury caches of seeds and nuts for lean times; when they do not re-visit a storage area, the seeds and nuts may germinate to create new trees.

 

The agoutis eat other foods as well, including leaves, roots and fruit. They will sit on their hind legs and hold the food in their front paws to dine.

These cute animals mate for life; the young are unusual in that they are active right after birth. The mother takes them to nest sites dug by other animals so they can claim their own home burrows! The young then line their home with leaves and twigs.

It is worth noting here that the Costa Ricans are protecting their ground mammals and all other wildlife. The country was the first in Latin America to ban sport hunting in 2012; it is also forbidden to keep, import or export wildlife for the pet trade.

And finally we get to the smallest mammals we viewed during our August trip. Last year, our group had been surprised to find that a group of bats was flying into a hotel’s outdoor restaurant to roost each night. The staff accommodated the creatures, which they listed as two-lined bats. After reading about Costa Rican bats, I think these might be lesser white-lined bats (Saccopteryx leptura). It was interesting to see how they would hang by one leg as they engaged in some grooming.

This year, we came across a small group of similar-looking bats roosting under a bridge. They had white lines down their backs but appeared to be long-nosed proboscis bats (Rhynchonyceteris naso). Their colonies often number 5-10 individuals.

One of our most interesting walks took place the day after our bridge sighting. We were visiting a self-taught local artist named Cope, in La Union, Guapiles. He created a wildlife viewing site around his home where he welcomes tourists to see hummingbirds and other avians. He offered to take us into the nearby forest to find a particular owl (coming blog!), as well as a couple species of bats and some interesting amphibians.

While we may be used to thinking of bats living in caverns, various species in the rain forest have found other roosting sites. The tent-making bats (Uroderma bilobatum) create a home by biting through the middle vein of a large leaf so that the sides droop down and form a hanging shelter. The structure is recognizable and after Cope found us a couple tents, members of our group knelt or hunkered down so we could peer upwards at the sheltering mammals.

 

At one site, after photographing the bats, I unfortunately stumbled backwards after taking a photo; I startled the bats, who took off in haste. Apparently, it is known that they spook easily since the slightest movement of their leaf could indicate that a predator is approaching. Cope fortunately located another tent so that the other group members could peer upwards at the creatures.

Our guide was kind enough to use people’s cell phones to take photos of the little bats.

At another tent, it turned out that adorable Honduran white bats (Ectophylla alba) were roosting. Of the approximately 1300 known bat species, only six have entirely white fur.

These bats are frugivorous, with one fig species being a preferred food.

The Honduran white bats are unique in being able to convert lutein into a form that better helps protect the retina and it is speculated that understanding how they do this could be helpful in the treatment of macular degeneration.

Our final bat species had a different type of residence – a termite mound, which may be abandoned or actively harboring termites. I believe that the species we saw was the pygmy round-eared bat (Lophostoma brasiliense), an insectivore although it will also eat fruit. Their daytime roosting site is maintained by a resident male bat, who prevents termites from repairing the cavity made by the bats. Seeing these nocturnal mammals in an unexpected home was truly an interesting way to conclude our bat-watching outing.

 

Many thanks to Nan DeWire and Ylva Byars for letting me include photos they took in this blog. After a foray into North Carolinian wildlife in the next posting, it will be back to Costa Rica to take a look at the woodpeckers there – and elsewhere!

Costa Rican mammals, part 1 – those similar to our Carolina wildlife neighbors!

While the trip I took this past August to Costa Rica was mainly focused on birding, our guides fortunately were also quite willing to stop and look for mammals, amphibians, reptiles and insects – people after my own heart! Here I’ll focus on some of the mammals we saw, starting in this 2-part blog with those that were familiar.

Fellow traveler Nan especially was drawn to the canines we came across – there wasn’t a dog (Canis) that she was unwilling to pet!

 

And they often were very cute.

 

As we drove from one destination to another, it was not uncommon to see light-colored cattle (Bos taurus) grazing in fields. It turns out that about 75% of the country’s cattle are found in Guanacaste province (where we started our trip) and that the Brahman breed is the one commonly raised for the meat industry.

I saw mostly cows, but during a visit to southern Costa Rica last year, we also saw a laid-back steer.

 

There were horses (Equus caballus) grazing in some fields and mountain valleys.

Everywhere we went, there were squirrels scurrying about on the ground, in trees and at feeding stations. The most commonly seen squirrel in the country is the variegated squirrel (Sciurus variegatoides), which varies in color from gray hues to dark brown colors.

  

This species spends most of its time in trees and does not hoard food.

 

Their main dietary selection consists of various seeds, although they also eat acorns, fruit and insects.

   

Another cute rodent is the red-tailed squirrel (Notosciurus granatensis), which is usually found in the cloud forests and wet/humid areas.

Although in some places, people warn against feeding mammals, we saw a red-tailed squirrel enjoying fruit at a restaurant that attracts tourists with its plants that attract hummingbirds.

 

While we do have wild boars in some mountainous North Carolina counties, as well as feral swine in Eastern coastal areas, we will not see collared peccaries (Pecari tajacu) roaming our forests and woods. They share some characteristics of the pig family but are not classified as pigs.

They are both carnivorous and vegetarian, even eating tulip bulbs, which are poisonous for humans. It’s said they usually ignore humans and that was the case for this peccary, which paid us no mind as it plodded about the gardens in one reserve.

 

Our final, at least partly familiar, mammal was observed near the restaurant of a hotel where we stayed. We were lucky to see it since these animals are both arboreal and nocturnal. Fellow birder Ylva got a nice photo of the visiting Central American woolly opossum (Caluromys derbianus). Not only is this marsupial a real cutie, it is also a nectar feeder, pollinator and seed disperser so that we got to see a species that fulfills multiple roles in its rain forest habitat.

Next up – the mammals we won’t see in North or South Carolina (yet).

‘Rassing – a surprise visitor – what a delight!

(Warning – this is a bit of a long blog!) Several years ago, what was likely a rufous hummingbird took up residence in my yard during the winter months. That was really unexpected — while it’s not uncommon for migrating or some resident hummingbirds (especially ruby-throats, Archilochus colubris, above) to spend wintertime in North Carolina, particularly along the coast, it’s not so common in the central part of the state. That experience taught me that it’s a good idea to keep up a nectar feeder in the winter as you never know when a stray migrant might show up. In 2015 and 2016, I traveled with fellow birders to visit people who had a buff-breasted (Amazilia yucatanensis) and calliope hummingbird (Selasphorus calliope) wintering at their homes. In actuality, however, I didn’t really expect a rare passerby in my yard.

 

It was consequently with great surprise that I saw a hummer hovering at the nectar feeder last week. “Oh, wow!” I thought; “a ruby-throated hummer is passing through as a very late migrant.” I grabbed my camera to take a few shots and immediately felt perplexed.

 

The bird looked like he had a purple rather than ruby or red gorget (throat feathers). The white patch behind his eye also showed prominently because of his very dark head.

To me, it also looked as if this hummer had blue patches on his tail feathers. (Most say his flanks are green and a hummingbird expert said he has iridescent black tail feathers; the way the light reflects off them made me see blue, however.)

I got a few photos and cautiously asked birding experts on a facebook group if he could possibly be a black-chinned hummingbird (Archilochus alexandri), also sometimes known as the Alexander hummingbird. It seemed unlikely as their normal range is the Western part of the Northern hemisphere, reaching north into Canada (Alberta and British Columbia), east to Oklahoma, and as far south as Mexico, where most spend the winter.

A couple people thought I might be correct, but most thought it was a ruby-throated hummingbird. My spring-summer ruby-throated residents had left at least a month ago but I thought perhaps a late migrant might have arrived. The next day, I saw the bird again and became convinced that it was a black-chinned hummer; his purple gorget was very obvious to me. I posted new photos and now the experts agreed that I was correct. That was very cool – I got a lifer without even leaving my own yard!

 

A couple days later, North Carolina’s hummingbird researcher, Susan Campbell, came to my home to band the unusual visitor. I invited a friend who had been to bird bandings in my yard before to come for the happy event.

Susan arrived early and first set up a cage trap for ‘Rassing (short for the Dutch word verrassing, which means surprise; I wanted him to have a name during his stay 😊). She left the door open with a long string attached and hung the nectar feeder on the outside. It wasn’t long at all before the bird arrived for a drink. When he left, Susan moved the nectar feeder inside the cage.

‘Rassing returned for another drink and flew right into the cage, which Susan shut promptly. She had already laid out her banding materials so she could remove him from the trap promptly.

He went into a small bag (the kind often used to hold birds for banding) which Lucretia held while Susan began filling out the paperwork.

Then the actual banding procedure began. Susan first checked his legs to ensure that he hadn’t been banded already – the hummers rarely show their legs so that was necessary.

Then she got ready to put a thin red metal band on his tiny leg with a silver band showing his numeric code for identification in case he is caught again some time (Band number 7100 (M)-41902).

She checked the length of his bill – 19.19 mm. She also advised that bird feeders with long slits are not preferred even if the birds like them. It turns out that the thin slots can rub against the bill and wear it down, damaging the bill and making it vulnerable to infection. (I afterwards enlarged the slots into ovals and circles and went back to a couple other feeders I had with larger holes.)

She blew on his stomach feathers to check his fat; he was not a hefty bird but certainly a healthy adult male. His weight turned out to be 3.09 g. She also recorded his body length.

She stopped for a moment so I could take a few photos trying to get a good shot of the purple gorget. It looked like ‘Rassing was trembling but this was the vibrations from his rapid breathing. (When resting at 91⁰ F, they take about 245 breaths per minute; at 55⁰ F, this rises to 420 breaths per minute!!) Susan thought he was acting fairly calm.

She measured his short tail (23.5 mm), as well as his wings (40.42 mm). The female black-chinned hummer would have more rounded wing feather tips than this male.

 

Susan took a few photos of ‘Rassing and he got a few long drinks from a feeder held by Lucretia. Then Susan gave me the honor of releasing him – and to my delight, he chose to sit in my hand for what seemed to be at least 90 seconds. I could feel him breathing and it was a real thrill to see him so close. With a little flutter of his wings he took off – and then stayed away from the feeder for quite some time.

 

I added a feeder in the backyard and ‘Rassing began preferentially feeding there – perhaps the front yard had acquired some unpleasant memories. However, at the end of the day, I would remove the backyard feeder so that visitors who wanted to see him had a better chance of seeing him dine at the front-yard feeders.

 

 

A fair number of birders were interested in being able to add him to their life, state and county bird lists, so I offered to schedule visits through a birding listserv for a few people at a time. ‘Rassing appeared more reticent to stay at the feeder when there were more than 2 or 3 people watching, which is understandable. Who wants an audience for each meal and snack you eat??

When it rained, the feathers atop his head clumped together, giving him a new “hair-do.”

 

 

It appears that this species of hummingbird has not been studied much. I found his behavior interesting and spent a good amount of time observing him (chores had to wait). When I watched him leave the feeder and go to a nearby tree, he would sometimes watch me (turnabout fair play, of course).

 

 

He seemed very comfortable with lots of other bird species at nearby feeders. Perhaps it gave him a safer feeling.

‘Rassing tended not to sit on feeders, as ruby-throated hummers often do. Instead, he mainly hovered and vigorously pumped his short tail quite a lot. I learned that this tiny bundle of energy was breathing at a flight rate of about 1260 beats per minute!

 

Occasionally, you could see the band on his leg but mostly he kept his legs tucked into his body.

In the evenings, he came around nearly the same time each day to have a longer drink and then he sometimes perched while feeding.

 

A Cornell University website says that black-chinned hummers rarely stay at a feeder longer than a day during migration, even when food is scarce. In my yard, he had access to lots of bugs (I have a small pond) and three types of sage/salvia were still blooming. Indeed, he sometimes came to the feeder with pollen covering the top of his bill.

Yesterday morning, ‘Rassing apparently had decided it was time to move on. After the warmest Halloween on record in our area, the temperature plunged during the night to the 30s. The next morning was the same and he may have decided it was time to go to warmer climes.

 

I did feel lucky that he graced my yard with his presence for a week; it gave me something to celebrate during a personally challenging time. The oldest known black-chinned hummer was more than 11 years old; if ‘Rassing likes going east during migration, perhaps he’ll stop by again next year – wouldn’t that be a tremendous surprise! 😊

 

“Wattle” I do to get a better photo of you?

In mid-August 2019, it was my privilege and good fortune to participate in an interesting, engaging and VERY fun “Birding Plus” tour in Costa Rica thanks to a great roommate, Nan, knowledgeable guide and tour organizer, Steve and Sherry, and group of fellow travelers (Ann, Art, Bill, Gordon, Len, Tom and Ylva). My next blogs will mostly focus on the birds, amphibians, mammals and insects we were fortunate to see there. The photos are not all great as taking shots in the rain and dark cloud/rain forests was challenging for multiple reasons. But they will give you an idea of the fascinating and beautiful sightings we had. (Clicking on photos enlarges them; then back arrow.)

One of the most difficult birds to “capture” in a good photo was likely the one about which I was most excited, the three-wattled bellbird (Procnias tricarunculatus). This species, which also lives in Honduras, Nicaragua and Panama, only breeds in the mountains of Costa Rica. These bellbirds are known to be shy, secretive and elusive as they remain mostly in the dense, high canopies of the forests. They apparently prefer to perch on uncluttered branches that are 33-72 ft (10-22 m) high and 0.98-2 in (25-50 mm) in diameter.

The males usually sing from March through June, so we were lucky that some of them were calling out in mid-August. Here we see a couple digiscoped photos of a male bird. The females look very different with olive coloring and a streaky yellow breast (we did not see a female). They are quite different in size, with males in one study having a mean wing length of 6.5 in (165.5 mm) compared to 5.7 in (145.1 mm) for the females.

 

 

The common name for these birds comes from the sound they make. In some articles, it is described as a 3-part song. To me, it sounded like they first made a high-pitched brief screech, squeak or whistle sound and then a deeper call.

 

Others have described their calls/songs as a “boink,” “bonk” or “Hee-aahh” sound. In any event, they obviously work at producing the sound. As we watched, “our” bird would open his mouth very wide, so that you could see the white and black lines surrounding the bill.

He seemed to be breathing in plenty of air as he sat there silently for a while. You could see his neck getting ridges, which I assumed was due to the oxygen he was gathering and holding to be expelled in the call. (This turned out to be a correct assumption according to one study!)

Then, he moved his head up and down a bit and you knew the sound was coming. It is unmistakable once you have heard it as in this brief video that fellow traveler Ylva made.

It is said that the bellbird’s sound is one of the loudest avian calls, audible to humans who are more than 0.5 miles (0.80 km) away. The calls and songs are not instinctive – the birds learn the calls and there are different “dialects” among the birds from different areas! One bird studied in Costa Rica could perform the song/call repertoires of Talamanca and Monteverde – in other words, he was bilingual!

 

Research has also shown that immature male bellbirds not only take 6 years to achieve their full adult plumage but also to perfect their entire song repertoire! Kroodsma et al. also note that: “Males appear to be highly attentive to the nuances of songs produced by their competitors, as both immatures and adults visit each others’ display perches, listening there for up to several minutes at a time.”

The other really striking characteristic of this species is the three wattles on the male’s head which begin growing when he is 6-12 months of age. One dangles from each side of the bird’s mouth and one is affixed to the base of the upper bill.

The wattles have been described as “wormlike”. Nan and I thought they looked a bit like hair-braids and on the flight home I sat next to a woman who had three braids ending in a point with interwoven gold thread that immediately made me want to give her the nickname “Bellbird”. (I didn’t tell her that though.)

The wattles are about one-third of the bird’s size (9.5-12 in or 25-30 cm). They cannot be controlled by muscles or made rigid, but they can be extended in length up to 3.9 in (10 cm) when the bird is interacting with others or singing.

The birds are frugivorous (eat only fruit) and prefer wild avocados (Lauraceae). They play an important role in the tree’s seed dispersal.

 

Due to habitat loss and hunting, the numbers of the three-wattled bellbird have declined to about 20,000 individuals and the International Union for Conservation of Nature (IUCN) has declared its conservation status to be vulnerable. They obviously inspire artists in Costa Rica, however, as witnessed by a mural at a restaurant where we stopped for lunch.

 

 

After three blogs in quick succession, I’ll now take a break to process and sort some more photos from Costa Rica to share with you. In the meantime, bye bye from the bellbird!

Further information

Summer hummers – entertainment for free: part 2

In my yard this summer, the ruby-throated hummingbirds (Archilochus colubris) came late to the feeders (similarly to what other people in the area had reported). Now, there are at least four vying for the four feeders, claiming territory for their own.

 

 

One bird in particular is most likely to be seen enjoying the garden flowers, including blue-black sage (Salvia guaranitica) and hot lips salvia (Salvia microphylla ‘Hot Lips’). In the first two photos below, you can see as his throat starts to bulge more as he sucks up the sweet nectar to complement his mostly insectivorous diet.

 

 

The airborne nectar droplets indicate that sometimes this hummer is a messy eater — or must leave quickly as another hummer is almost literally on its tail.

A couple of the birds spend a lot of time near the nectar feeders, perching close by to chase off anyone who comes near.

 

 

 

They each have favorite perching spots from which they can observe if an “intruder” is coming near the feeder they have claimed.

 

 

Sometimes, they fly up to a higher perch so they can see both the front and back yards – a necessary vantage point if they want to keep an eye on where everyone is.

 

Most ruby-throats have 940 feathers, all of which are replaced each year. As they take little rests, they stretch their feathers and may also groom them.

When a rival approaches, they spread their rectrices (tail feathers) – both when sitting and in the air.

 

Their feathers are beautifully arranged, looking like scalloped decorations.

 

They make frequent trips to the feeders and then occasionally “air out” their tongues.

 

The bill of the ruby-throated hummingbird is one of its most distinctive features. It measures about 0.59-0.79 in (15-20 mm) in length and is said to open no more than about 0.39 in (1 cm wide) at the tip. The hummers in my yard seem to be able to open their mouths to varying extents, however. They consume nectar by extending and contracting their tongues up to 13 times per second.

 

 

 

A quick, only few-second nap is also a frequent behavior. The hummers are almost constantly at the feeders and thus bulking up for their long migration, but they also expend considerable energy chasing one another away from feeders and flowers!

 

 

 

The hummers are not fazed by weather, zipping around rain or shine. Putting on weight and strength for their autumn migration down south is important for survival!

These minute marvels are such a pleasure to watch; I will certainly miss them when they begin their journeys to their wintering grounds.