As part of my birdwatching tour of Costa Rica with Tropical Birding, we visited the Tárcoles River, also called the Grande de Tárcoles River or the Río Grande de Tarcoles, in Costa Rica. It originates on the southern slopes of the Cordillera Central volcanic range, at the confluence of Virilla and Grande rivers, flows south-west, passing by the Carara Biological Reserve, drifts into the Guacalillo Mangrove Estuary and eventually empties in the Gulf of Nicoya in the Pacific Ocean. Although the river is somewhat polluted, it is significant for the country’s residents, as nearly 60% of Costa Rica’s total population lives along its basins. The river is perhaps best known for its abundance of American Crocodiles. It’s said that the Tárcoles River has one of the highest populations of crocodiles in the entire world, up to 25 crocodiles per square kilometer. Several tour operators take advantage of this fact by offering river tours that guarantee croc sightings. Much of the time these large reptiles (which can grow to a length of thirty feet) can be spotted swimming through the river or sunbathing along the banks. In addition to the crocodiles, the river also supports more than 300 species of migratory, native and coastal birds. Located on the Central Pacific Coast of Costa Rica, the Guacalillo Estuary and the Tárcoles River offer the chance to observe the one of the richest mangrove forests in the mid pacific coast and the most important conservation area for the Scarlet Macaw in the country.
Tárcoles River Bird Cruise
One of the issues you have to accept with photography and birdwatching is the early mornings. We got up before sunrise to board the boat in Tarcoles, Puntarenas. Forming the northern border of Carara National Park and situated in the transition zone between the Tropical Dry Forest to the North and the Pacific Rainforest to the South, the Tarcoles River is the meeting place for an incredible abundance of bird life. Our tour started by going up the river in search of resident birds, surrounded by beautiful pastures. The water was so still, you could see the reflection of the sky and it was difficult to even identify the shore. Then, we went down to the Guacalillo Mangrove Estuary, where you can find four different species of Mangrove: the buttonwood (Conocarpus erectus), the red mangrove (Rhizophora mangle), the white mangrove (Laguncularia racemosa) and the black mangrove (Avicennia germinans). This beautiful ecosystem is home of the colorful scarlet macaw, the northern jacana and the mangrove swallow. Finally we went to the mouth of the river for more bird watching, where coastal birds such as brown pelicans, cormorants and raptors can be seen.
Ibis, Herons and Egrets
They have a nice collection of birds on the upper stretch of the Tárcoles River. The American White Ibis (Eudocimus albus) were in breeding plumage with light pink bills and legs. The largest heron in North America, the Great Blue Heron (Ardea herodias), and the slender but colorful Tricolored Heron (Egretta tricolor) with a mix of blue-gray, lavender, and white looked stunning in the dawn light. Love was in the air for the Bare-Throated Tiger Herons (Tigrisoma mexicanum), whose ability to extend the neck defies explanation. The Green Heron (Butorides virescens) was motionless as usual with deep green wings and a mahogany chest. You have to look closely to see the creamy yellow crown and face patch of the Yellow-Crowned Night Heron (Nyctanassa violacea). I actually found this shy Boat-Billed Heron (Cochlearius cochlearius) in the mangrove forest sleeping. The large eyes are an indication of their foraging behavior, which takes place at dusk and early night. During the breeding season, adult Snowy Egrets (Egretta thula) develop long, wispy feathers on their backs, necks, and heads. In 1886 these plumes were valued at $32 per ounce, which was twice the price of gold at the time. Plume-hunting for the fashion industry killed many Snowy Egrets and other birds until reforms were passed in the early twentieth century.
Marsh, Stream and Other Waterbirds
The Amazon Kingfisher (Chloroceryle amazona) looks a little like the Green Kingfisher but it is larger and has no white spots on the wings. The Double-Striped Thick-Knee (Burhinus bistriatus) is a mainly nocturnal bird with big, yellow, owl-like eyes, it may have been looking for a place to sleep. The Collared Plover (Charadrius collaris) and Spotted Sandpiper (Actitis macularius) are little shore birds common along coasts and riverbanks. The Neotropic Cormorant (Phalacrocorax brasilianus) can be confused with the Double-Crested Cormorant (Phalacrocorax auritus) even though they have very different ranges. A bird of the tropical waterways of Central and South America, the Neotropic Cormorant reaches the upper limits of its range in Texas. The Neotropic Cormorant has a shorter beak, a longer and rounder tail, appears more slender and has beautiful emerald green eyes. We found a large group of Brown Pelicans (Pelecanus occidentalis carolinensis) and Magnificent Frigatebirds (Fregata magnificens) resting together in several nearby trees. The brown pelican is the national bird of Saint Martin, Barbados, Saint Kitts and Nevis, and the Turks and Caicos Islands, and the official state bird of Louisiana. Magnificent Frigatebirds (Fregata magnificens) are the only seabirds in which the male and female look strikingly different. Females may not have the males’ bright red pouch, but they are bigger than males. These master aerialists are also pirates of the sky, stealing food from other birds in midair.
We managed to see four birds of prey at the end, near the mouth of the river. Unique among North American raptors for its diet of live fish and ability to dive into water to catch them, Ospreys (Pandion haliaetus) are common sights along shores and waterways. The Osprey is the second most widely distributed raptor species, after the peregrine falcon. It has a worldwide distribution and is found in temperate and tropical regions of all continents except Antarctica. The Gray Hawk (Buteo plagiatus) is found from the U.S. Southwest to northern Argentina and Paraguay. Habitat varies from open thorn-scrub and savanna to tropical forest edges and clearings. The Crested Caracara (Caracara cheriway) looks like a hawk with its sharp beak and talons, behaves like a vulture, and is technically a large tropical black-and-white falcon. You cannot mistake it’s appearance and it seems to be pretty fearless. The Yellow-Headed Caracara (Milvago chimachima) is found from Costa Rica south through Trinidad and Tobago to northern Argentina. While not quite as aggressive as the Crested Caracara, it will eat reptiles, amphibians and other small animals as well as carrion.
As always, I hope you enjoyed the post, if you are interested in birds the Tárcoles River is a great place to see them in Costa Rica.