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!

Quebec chronicles – birds I know in their summer habitat

As I sit here in the 34 ⁰C/93 ⁰F temperature, a memory of cooler weather in Quebec this past spring beckons. So here we go back to the birding trip I took with some friends at the end of May/start of June. While I was able to see several “lifers” (birds I saw in person for the first time) during that trip, there were also a number of birds I had seen here in North Carolina (NC) but who were now getting ready for breeding on their summer grounds. These included some aquatic species, like the American black ducks (Anas rubripes, above), who interbreed with mallards, and a lovely pair of American wigeons (Anas americana), who are one of the more vocal duck species.

 

At one pond, I surprised a female ring-necked duck (Aythya collaris), who took off in a flurry of wings. These ducks tend to prefer small bodies of water as resting and feeding areas. Later that afternoon, I caught sight of a male counterpart at the far side of another pond as our car passed that body of water.

 

The spotted sandpiper (Actitis macularius) is a shorebird I have seen with some regularity in my home territory in NC. The Northern harrier (Circus hudsonius), which I don’t see as often, is nevertheless a familiar bird.

 

The double-crested cormorants (Phalacrocorax auratus) would fly by on the St. Lawrence Seaway from time to time. I see them often in NC but had not seen the somewhat unusual-looking (to me!) surf scoters (Melanitta perspicillata). The male has what has been described as a swollen bill with patches of white, red and orange color contrasting with its black feathers.

  

A duck that I had seen for the first time in North Carolina, when one paid a rare visit to a lake in our area this past winter, was the long-tailed duck (Clangula hyemalis). These deep-diving birds breed along Northern sea coasts, lakes and on tundras. There were two males swimming at one place that we stopped – one was in its breeding plumage while the other still sported its winter feathers (with a large round black spot on its face, above). Our local birding pal speculated that the winter-plumage bird might not have been completely healthy and was therefore not going to breed.

A female long-tailed duck was very busy in the meantime diving under water, although she was apparently looking for food close to the water’s surface rather than diving deep (i.e., up to 60 m or 200 ft).

 

The water was really beautiful, looking almost velvety to me as it undulated in gentle movement with the long-tailed ducks and a common goldeneye (Bucephala clangula) riding the swells.

On several occasions, we were lucky to see common eider ducks (Somateria mollissima) in the distance. Eider down, which has been used to stuff humans’ pillows, comes from the female duck’s breast and is intended to be used in lining her nest. Nowadays, there are communities in Norway that protect the birds’ nests, eggs and young so that they can later harvest the down from the used nests.

A group of common murres (Uria aalge) flew by one day and, like the eiders, were added to my list of Quebec lifers. The murres are a type of auk, birds that can swim and dive wonderfully but have an awkward gait when walking on land. The murres don’t breed until they are 4 or 5 years old, in contrast to many other birds.

A really beautiful water bird, which I unfortunately was not able to photograph beautifully, was the common loon (Gavia immer). When the light hits its head and neck feathers in the right way, they have a beautiful green-blue iridescence. With its checkered back pattern and white-and-black striped collar, these birds make me think of someone getting ready for a formal dining party, i.e., they are well-dressed avians!

 

We only saw a Canada goose a couple times during our stay in Quebec but did get to  see another species, the brant goose (Branta bernicla). This species almost died out along the eastern coast of North America when their main food, eelgrass, suffered a blight. The birds changed their diet to include sea lettuce and this proved to be a good survival strategy.

 

On land, one afternoon I spotted a sparrow in the garden of a private home. Though I couldn’t get too close, I got an identifiable photo and learned it was a Lincoln’s sparrow (Melospiza lincolnii), which I had not seen before. This species was named by James John Audubon for his friend, Thomas Lincoln, who shot one of the birds during a trip they took together in 1834. (Obviously, one of the sadder aspects of birding in Audubon’s time.)

Another, much larger bird, that I got to see for the first time was a ruffed grouse (Bonasa umbellus). These birds can be found in Appalachia, but it was only in Quebec that I was able to view these birds three times.

They tend to walk around much of the time but also fly up into trees to forage. We saw them in quaking aspen trees (Populus tremuloides); it turns out that dormant flower buds of male aspens are a major food source for the grouse in winter and early spring.

 

Unfortunately, these birds have been succumbing to West Nile virus in some of their habitats.

Finally, two birds that we saw in great abundance were birds that also appear with regularity on birders’ lists in NC.

 

According to the Cornell Lab of Ornithology, it is far more likely to hear than to see the Swainson’s thrush (Catharus ustulatus); however, it seemed these birds were out and about at every place we stopped.

The initial excitement at seeing one slowly turned into remarks of “oh, another Swainson’s” as one, two, three or more of these charming birds worked the meadows and trail paths looking for sustenance.

 

The same thing eventually happened with our sightings of least flycatchers (Empidonax minimus), one of the smaller birds of its type. These birds like to snatch their meals from the air but will also glean insects from leaves and twigs.

 

 

 

What I did find is that these small companions on our walks were quite charming and cute, so I didn’t tire of seeing them again and again.

 

Next time: some of the non-avians we saw in the Canadian province!

My special bird in autumn 2018

Well, having had time to finally process photos as the year end approaches, I’m “on a roll” with posting blogs in contrast to other months in 2018. I have two more to post on mammals this year. This one is to commemorate a real birding treat that came to me during the snowstorm that was featured in my last two blogs.

 

There had been reports on birding sites and listservs that some bird species which usually don’t come too far south during the winter were on the move this year to warmer climes. They included birds that sometimes arrive in North Carolina (NC) in winter, but who don’t always come in large numbers (an “irruption”) such as pine siskins (Spinus pinus, above) and purple finches (Haemorhous purpureus, below).

  

I’ve also been lucky to see red-breasted nuthatches (Sitta canadensis), another irruption species, either in my yard or on nature walks.

 

So why are they coming here in numbers?  It turns out that trees in the northern boreal forests are not producing enough food sources that these birds need to survive winter weather such as conifer seeds and berries (from trees such as hemlock, spruce, firs, alders and larch).

What was really exciting for birders in NC, however, was that some other bird species are also seeking new winter foraging areas. They include redpolls, crossbills and the gorgeous evening grosbeaks (Coccothraustes vespertinus) who are seen here only rarely.

I had only ever seen a photo of these grosbeaks and thought it would be fun to see one in person. Members of a listserv mentioned that these grosbeaks had been spotted in Virginia, just above the NC border, so we should be prepared to perhaps see them.

On my visits to the Brumley Nature Preserve, I spent time in the spruce areas in the hope of spotting one, but I had no such luck. And then as the snow was falling heavily on the first morning of our snowstorm, I caught sight of a bright yellow and black bird on a feeder as I looked out my window. Lo and behold, when I grabbed my camera I discovered a male evening grosbeak on a feeder!

What was even more exciting was that he was accompanied by two female birds, both of whom were very lovely as well. I took lots of photos.

They finally flew off and I counted myself very lucky indeed. A while later, when the snow had stopped for a while, I was watching the feeders again and the threesome returned to my delight. They fed and then rested on feeder poles.

I tried to go outside quietly so I could photograph them without a window between us but they were quite skittish and left quickly as soon as I appeared. They flew to the tops of nearby tall pines and then disappeared off into the distance. They were not shy when I stood in front of the living room window, however.

The trio reappeared a third time and I stayed behind the window to admire them. It was interesting to see how they could look different, depending on their posture. The bird above looked “tall” as it fed next to the Eastern bluebird. And then the other looked fat and fluffy on the feeder pole – even looking as if it had an outsized head when it leaned forward a bit!

 

They left in the afternoon and did not return, even when it snowed again the next day. A fellow birder who lives northwest of me spotted a male evening grosbeak on one of her feeders that day – the birds were obviously en route to another destination. I hope they found a good food source area for the rest of the winter. And my photos will remind me of their wonderful visit, which made this snowstorm one to remember. 😊

An avian buffet appears!

In the town where I live, there is a private lake in a neighborhood of single-family homes. The little body of water was created by developers who dammed a local creek; now a neighborhood association levies annual fees for use of the lake for swimming, fishing and boating. In the past month, the neighborhood residents were surprised by an influx of birds that they do not usually see and some photos of the new avian visitors began circulating.

Given my interest in wildlife and birds, some colleagues passed on a couple of photos to me and one couple kindly invited me to come visit so that I could see the new arrivals in person. They were especially curious about the identity of a few ducks. When I arrived, no ducks were in sight, but at least 80 double-crested cormorants (Phalacrocorax auratus) were hanging out in crowds on two floating docks.

Their tightly-packed presence had displaced the Canada geese (Branta canadensis), who are more common lake residents. A group of 11 geese were off in the distance on shore leaving the open water to the visiting avian groups.

Some of the cormorants couldn’t fit onto the platforms, so they swam around in the company of the many dozens of ring-billed gulls (Larus delawarensis) of all ages who were swarming the waters as well.

From time to time, the gulls would begin edging their way onto the platforms, eventually taking up space vacated by the cormorants. There are both adult and immature gulls in the crowd.

From time to time, the gulls launch themselves into the air for aerial forays which end in dives down to pick up a fish, of which there still seem to be plenty. This is because the shad population with which the lake was apparently stocked is dying off as a whole.

Why is this happening? I don’t know the species of shad with which the lake was stocked, but it appears that threadfin shad (Dorosoma petenense) are common in the Southeastern USA and often introduced as forage fish for the bass and catfish that fisher-people seek. The shad are very sensitive to changes in water temperature; when it goes below about 42° F (5.5° C), they expire. In the past 6 weeks, we had an unusual early winter storm with about 8-11 inches of snow, followed by days and days of cold rains. Sometimes, it is cold 24 hours long; other days have nights and dawns below freezing and then afternoon temperatures of 50-60° F (10-17° C). The shad die-off is a result.

  

The newly arrived birds are obviously enjoying the easy pickings. When the gulls drop down to snatch a fish, they are almost always pursued by other gulls who try to make them drop the prize.

 

Even when they alight with a fish firmly held in their beaks, other gulls harass them in an attempt to make them give up the meal.

 

  

The shad often appear to be too large for the gulls to swallow. I saw several gulls try to position them to get them down their gullets but the fish just wouldn’t go down. So they drop the fish in the water and then try to pick off pieces for easier eating, while fending off neighboring gulls.

  

It is unclear to me how the birds who don’t usually populate the lake in winter knew that a spontaneous buffet had appeared. In addition to the cormorants and gulls, a group of seven bald eagles (Haliaeetus leucocephalus) was also fishing when I visited. There were some almost full adult eagles (with mostly white heads and tails) and several immature birds of varying ages (eagles reach maturity at 5 years of age). I guess that they came over from Jordan Lake, which is quite a fair distance away. Searching the Internet has not yet given me an answer to this question.

I didn’t see the eagles harass gulls who had gotten a fish but they were very carefully watching one another. When the eagle below managed to get a snack, other immature eagles closely followed him/her. A sub-adult who got a fish was harassed by an immature bird as well.

 

The eagles soared overhead and were joined at one point by a beautiful red-tailed hawk (Buteo jamaicensis). The larger raptors let the hawk fly alongside them with no problem.

It was quite a chilly morning when I got to see the visiting aquatic birds, so I only stayed a short time. But my friends invited me to return for another visit, which I hope to do soon as there is no telling how long it will take the visiting birds to eat the easily available shad. And the ducks? I was able to get one rather indistinct photo of a threesome across the lake and helpful folks in a Facebook group confirmed my guess – they are ruddy ducks (Oxyura jamaicensis). Maybe I can get a decent photo of them next time. 🙂

Winter wonderland – sharing and spats at the feeders

I thought I had published this blog in early February and just discovered that I had only saved a draft. Since we had snowflakes last night (in April!), I’m going to go ahead and post this now – a break in the series about Costa Rica! When the snow began falling during our day of one-foot accumulation, the feeders were inundated by some of the dark-colored bird species who tend to come in crowds. At first, they were peacefully sharing space.

 

  

Although I sometimes have a couple dozen red-winged blackbirds (Agelaius phoeniceus) at the feeders, during the storm only one pair showed up for a brief visit and the other birds left them alone.

 

The mourning doves (Zenaida macroura) often share feeder space with other birds, including those that are smaller than they are.

The common grackles (Quiscalus quiscula) are known to other people as domineering birds at the feeder, but those in my yard have always been polite, even though they seem to have a permanent expression that expresses anger.

 

 

The brown-headed cowbirds (Molothrus ater) sometimes share space nicely and sometimes fuss at one another as they vie for a good perch. They don’t try to chase off other species though and are not apt to “yell” at other birds.

The birds who do “yell” are the European starlings (Sturnus vulgaris). Young ones yell at their parents after fledging, begging to be fed. Adults yell at each other when they are trying to all crowd together onto a feeder. And adults yell at other species to drive them away so they can have all the space for themselves.

At my feeders, however, they have found their match in the male red-bellied woodpecker (Melanerpes carolinus). One day, I watched as they managed to intimidate him for a few minutes, but he then returned to the feeder and refused to give up. Now he is no longer frightened of them and stands his ground when a starling does its best to make him move.

    

It turns out that studies have shown that the red-bellied woodpeckers are the birds most apt to resist attempts by other birds to displace them from feeders.

The red-bellied woodpecker also was not intimidated by me at one point. He doesn’t like it when he flies in and notices at the last moment that I am sitting or standing on the porch; often he will swerve away and wait for me to leave. During the snow storm, however, he decided to display his displeasure with my close presence, both from a frontal and dorsal view!

 

  

      

 

I guess that the little bird spats do make for sometimes more interesting birding observations. Seeing the tiny ruby-crowned kinglet (Regulus calendula) warning off a rival a few days before and after the snow melted did show off a gorgeous and brave little bird.

 

 

I’m looking forward to seeing what the springtime observations of animal behavior will reveal.