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| Bare-necked Tiger-Heron on the Río Frío |
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| Neil, our boatman Chubby, Juan Diego |
This slow-moving muddy river flows out of Caño Negro, emptying into the huge Lake Nicaragua in (well, you guessed it) Nicaragua, which was just a few miles away.
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| The Río Frío offers beautiful flora and fauna |
During the rainy season from May to October, the Río Frío overflows its banks to form Lago Caño Negro. The water level falls continuously for the next three to four months until all that is left is the main channel of the Río Frío. Since we were at the end of the dry season, parts were quite shallow.
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| Río Frío |
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| We had to navigate around and over lots of obstacles |
In the afternoon, we went the other direction to explore deeper waters.
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| Heather and Joyce viewing a Great Egret |
Although we saw a number of tour boats when we departed, most of the time, we were fairly alone on the river. The trips were leisurely, but packed with things to see.
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| A Black-throated Trogon on the shore |
So where to start?
A Special Side Trip
I will start with our rarest sightings, for which we had to get off the boat and traverse a very slippery, muddy hill to a “secret lagoon.”
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| Returning from our treacherous walk |
There we saw some distant Howler Monkeys and some Black-necked Stilts ...
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| A graceful bird |
… a Solitary Sandpiper …
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| All by himself |
… a Sulphur-bellied Flycatcher …
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| Posing on an interesting tree |
… and a beautiful Black-headed Trogon …
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| Looking simultaneously goofy and gorgeous |
Bingo! We got both.
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| Coming out of the vegetation for just a minute |
Often called the “most beautiful Heron on the world,” the Agami Heron has a couple of other names, including Chestnut-bellied Heron and Hummingbird Heron.
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| A nice reflection |
About 30 inches long, it is short-legged for a Heron, but has an extraordinarily long bill. The one we saw was hiding in the vegetation by the river, only venturing out briefly two times.
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| Look at the length of that bill |
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| More detail; Photo: eBird |
But, it’s a bird rarely seen in the open (or at all). Its habitat encompasses swamp forests, mangroves, forest streams and freshwater wetlands.
I wish I could have gotten a sharper picture, but at least I got some photos.
During this little foray, we also saw an even-harder-to-photography Green-and-rufous Kingfisher, which spent the entire time in a deep thicket. I managed one in-focus photo.
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| Green-and-rufous Kingfisher hiding in the thicket |
But, once again, better than nothing for this somewhat rare bird.
Kingfishers
Speaking of Kingfishers, we had seen many before during this trip, but nothing like the volume we saw on the Río Frío. The majority here were Green …
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| Female Green Kingfisher |
… and Amazon …
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| Male Amazon Kingfisher |
I think we may have seen an American Pygmy on the Río Frío, but I am not positive. I didn’t get a photo of one there.
We definitely saw several Ringed Kingfishers, as well ...
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| Ringed Kingfisher hiding in a tree |
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| The bill is amazing |
We saw all six of the different species found in the Americas on this trip.
All Kingfishers have large heads, long dagger-like bills, short legs and stubby tails. Most species have bright plumage, often green or blue, with small differences between the sexes.
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| Amazon Kingfisher with lunch |
Kingfishers hunt by swooping down from a perch, usually with great velocity.
While many live away from water and eat small invertebrates, the ones in Costa Rica are water-loving fish-eaters, although they also eat insects and amphibians.
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| They cock their tails up |
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| A female Amazon Kingfisher preening |
The Amazon Kingfisher is about 12 inches long. It is solid green above, with a shaggy crest and a white collar around the neck. Males have white underparts, a broad chestnut breast band and some green streaks on the flanks. Females have white underparts with green patches on the side of the chest and green flank streaks.
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| Male Amazon Kingfisher |
The Green Kingfisher is 7.9 inches long. It is the same green as the Amazon, but with white markings on the wings and tail, and a white collar around the neck. Males have white underparts, a broad chestnut breast band and some green spotting on the flanks. Females have buff-white underparts with two green chest bands, the lower of which links to the green spotting along the sides of the belly.
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| Female Green Kingfisher |
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| Male Ringed Kingfisher |
Looking like a smaller version of the Ringed Kingfisher, the Belted Kingfisher is about 13 inches long. Both sexes have a slate blue head, large white collar, a large blue band on the breast and white underparts. The back and wings are slate blue with black feather tips with little white dots. The female features a rufous band across the upper belly that extends down the flanks.
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| We saw only a few Belted Kingfishers in Costa Rica; this was taken in Colorado |
The American Pygmy Kingfisher is only 5.1 inches long. It is green above, with a yellow-orange collar around the neck, rufous underparts and a white belly. The female has a narrow green breast band.
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| American Pygmy Kingfisher, taken at the Río Tárcoles |
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| Yes, this is the same Green-and-rufous Kingfisher photo |
Laguna Monica
In our deep-water part of the cruise, we went into a broad lagoon called Laguna Monica ...
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| A Ringed Kingfisher welcomes us |
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| There are at least a dozen here |
… and in the water around our boat …
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| They were everywhere! |
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| The eye ridges are very obvious |
The Spectacled Caiman has a ridge between its eyes that looks like the frame of a pair of glasses, which is where its name comes from.
Plus, there are pointed bony frames above their eyes. It’s one way to differentiate the caiman from the larger Crocodile.
Caimans can grow to up to 8+ feet and weigh 80-1,430 lbs.; the males are longer and heavier than females.
Light-colored, they darken during colder weather (is weather ever colder in Costa Rica?) to help better absorb sunlight.
Caimans have a long, tapered snout, an enlarged fourth tooth and sockets in the upper jaw that cradles the lower teeth.
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| Look at those teeth! |
The Spectacled Caiman can move rapidly when threatened, but is usually immobile, resting on shores or partly in water. In the rainy season, males become aggressive and territorial.
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| Getting ready to launch |
Usually hunting at night, the Caiman varies its diet seasonally. During the wet season, it primarily eats snails and freshwater crabs, while it mostly eats fish in the dry season.
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| What a smile! |
Smaller Caimans tend to eat more insects and freshwater shrimp, while larger ones more frequently consume mammals and fish.
Caimans build nests as a mound of dense vegetation in areas that are close to water but not at risk of being flooded.
Temperature is important to the developing eggs, so females build their nests in a way that insulates them from extreme temperature changes.
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| Lying in and digging in the mud, perhaps preparing a nest |
As the vegetation in the nests decays, the nests produce heat that can keep the eggs warmer than if they were insulated by mud alone. Heat not only incubates the eggs, but also determines the sex of the developing caimans. When the temperature inside the nest is about 90 °F or higher, the Caimans become female, and otherwise become male.
At the lagoon, there was also a lone Costa Rican Crocodile basking in the sun …
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| Costa Rican Crocodile (see how the eyes are different?) |
Plus, watching from a tall tree on the shore was a regal Black-collared Hawk …
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| Sitting quietly in a tree |
… Kingfishers were everywhere …
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| Following a dive |
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| They can be quite entertaining |
Water Birds
Of course, we saw a fair share of waterbirds, in and out of the lagoon, including a Boat-billed Heron that woke up to have a look at us as we cruised by …
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| Boat-billed Heron |
... a Limpkin with its rolling gait ...
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| Limpkin by the shore |
… Anhingas …
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| A female Anhinga dancing |
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| Left, Black-crowned Night Heron; Right, juvenile Little Blue Heron |
… more Black-necked Stilts husdand …
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| Look at those long, long legs |
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| Lots of pretty colors |
… and beautiful Snowy Egrets in their breeding plumage …
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| Great Egret |
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| One is having lunch; one is posing |
Bare-Necked Tiger-Heron
But, my favorite was the Bare-necked Tiger-Heron, which is named for its unfeathered throat that it expands when it is aggravated or vocalizing ...
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| That neck is so weird |
The bones in the neck form a tent-like arch when the throat is expanded. It’s quite a thing to see.
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| I mean ... |
We saw quite of few of these beautiful birds walking along the shore…
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| Beautiful plumage |
One was chasing a Social Flycatcher that fled and hid in a hole in the bank …
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| This little guy's mate harassed the Heron so he could get away |
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| Going up! |
According to what I read, Bare-necked Tiger-Herons eat fish, amphibians and crustaceans and, sometimes they will eat “large insects.”
It didn’t mention birds, but it sure looked like the one we saw was looking for dinner. Maybe it thought the Flycatcher was an insect.
Another one we saw demonstrated how it can raise and lower the crest on its head just in the few seconds it took us to cruise past it.
As I mentioned in an earlier post, the bird got its name from the striped plumage of the juvenile, which is said to resemble the stripes of a tiger.
On this day, we saw mainly adults, although we did see a couple of juveniles …
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| Juvenile Bare-necked Tiger-Heron |
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| Ouch! |
Watching these Herons on the shore drove home how difficult it is to live in the hot, humid, buggy environment of the Caño Negro wetlands. The legs of one of the Bare-necked Tiger-Herons we saw on the shore were completely covered with what appeared to be some kind of bee or fly. It looked terribly annoying. I suspect this also makes these birds susceptible to insect-borne diseases.
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| A beautiful bird |
Sungrebe
Another favorite on the cruise was a beautiful female Sungrebe, this one much closer than the distant one we saw at La Selva.
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| A beautiful and rare bird |
It swam along the shore as we cruised past, giving us quite a bit of time to appreciate its grace and beauty.
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| Sungrebe feet; Photo: eBird |
This duck-like bird is actually a Finfoot, the only living member of the genus and related to only two other birds, both found in Africa. Finfoots have broad lobes on their feet that they use to propel themselves in the water.
They are reclusive, preferring well-covered slow-flowing streams and secluded waterways, sometimes swimming partly submerged, like an Anhinga.
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| Such pretty markings |
Male Sungrebes have folds of skin under their wings in which they carry their young from hatching until the chicks are able to swim for themselves. This has led to them being called "Marsupial Birds."
We knew the one we saw was a female because it had bright orange-rufous patches on its cheeks and its bill was turning red ...
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| Breeding plumage |
Other Birds
We observed a wide variety of birds in the vegetation along the river, including a beautiful Gray-headed Kite …
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| Watching the river from a high vantage point |
… that was keeping watch at the top of a tree and then flew to another perch ...
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| Stopping to smell the flowers? |
… Chestnut-sided Warblers …
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| I finally got a good photo |
… Yellow Warblers …
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| Enjoying some riverside nectar |
… Variable Seedeaters …
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| A cute little bird |
… a Pied Puffbird …
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| This one was high up in the trees |
… and several other species …
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| CW: Montezuma Oropendola, Yellow-throated Vireo, Squirrel Cuckoo, Black-striped Sparrow, Pale-vented Pigeon |
Plus turtles and lizards …
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| Left, Meso-American Slider; Right, Emerald Basilisk |
... and, a contingent of the local cattle …
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| Brahman Cattle |
… who seemed very interested in us …
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| Two Brahman calves |
It was quite active along the edges of the river …
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| An Anhinga takes off |
The sky was even full of birds …
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| CW: Osprey, Lesser Yellow-headed Vulture, Broad-winged Hawks |
The Dock
We also saw a few birds at the dock as we were boarding and disembarking from our trips, including a Gray-headed Dove tucked away in the trees …
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| An odd-looking critter |
… and Northern Jacanas walking along the shore on their giant feet …
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| A common shorebird |
… those feet are so big and the Jacana is so light that it can walk across lily pads and similar vegetation floating on the surface of the water, giving it its nickname of “Jesus Bird” because it can “walk on water.”
Day's End
At the end of our second cruise, we watched a number of birds settling down for their evening roosts.
This included a large number of Cattle Egret …
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| A very large flock |
… some Wood Storks …
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| Coming in |
… Roseate Spoonbills …
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| Settling down for the evening |
… and a bird that we had been excited earlier to see two of because it has a very small range in southern Nicaragua and northern Costa Rica …
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| A great sighting |
… imagine our surprise when we saw about 70 Nicaraguan Grackles roosting for the evening …
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| This was just part of the flock |
Juan Diego said that seeing this many at once was quite unusual.
These boat trips on the Río Frío were among my favorite activities of the trip. Cooler than hiking, full of interesting – and surprising – sights. Just a very good day.
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| Happy cruisers |
The next day, we would be heading back to San José. And, then, we’d be heading out to the Osa Peninsula for more adventure.
Trip date: March 9-27, 2022
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