The Middle American Rattlesnake is a large, venomous snake. It has a drab color pattern, consisting of dark diamond-shaped blotches on a light brown base coloration. The key differentiator with all other venomous species in Costa Rica is the rattle, which produces a loud, menacing sound when it is vibrated rapidly. Indeed this sound causes fear in most people, as it is associated with the killer nature of these animals. Rattlesnakes however use this sound more as a defensive strategy, trying to scare off potential predators. As long as one is careful not to approach this snake more than it allows, it should be safe to watch them on their habitat.
The Side-striped Palm-Pitviper is a venomous snake, sharing its genus with the Eyelash Palm-Pitviper. The Side-striped is green, which helps to camouflage them in the rain forest, as it mainly has arboreal habits. It has a prehensile tail, which means that it can be coiled around branches that work as an anchor to keep its balance. It is moderate in size, less than 1 meter in length, typically between 60 and 70 centimeters. It has a light-blue postocular stripe. Juveniles are rather drab, having a brown skin.
The Annulated Tree Boa is a large arboreal species that inhabits the Caribbean side of Costa Rica. Unlike other Boa species like the Mesoamerican, one morph of this species are brownish-red in color, which renders them rather conspicuous against the dark green background in the tropical rain forest. Their nocturnal habits and preference for staying high in the trees make them difficult to spot. The color pattern consists of a series of diamond-shaped blotches, which are darker over the dorsum and lighter towards the venter. Some individuals have a cream base color instead of the brownish-red of the specimen shown below.
The Mexican Tree Frog is among Costa Rica’s biggest frogs. It is somewhat similar in appearance to the Masked Tree Frog, however the Mexican is bigger; its overall color is brown instead of green, and does not show such a definite dark brown patch behind the eye. The eyes are very similar between both species. It does occur in the Guanacaste province, from which the Masked is absent, however it is not found on the Pacific south from the Tarcoles river. They are nocturnal and arboreal like most tree frogs.
The Dwarf Glass Frog is the smallest Glass Frog to be seen in Costa Rica, roughly similar in size to a Strawberry Poison Dart Frog, but given its green dorsal skin it is more difficult to spot, specially if they stay motionless on a green leaf; increasing the probabilities of seeing one is the fact that they call from the upper side of leafs, so putting enough attention and following the direction of their call, one might discover an individual. Their eyes are more forward facing than the Dusty Glass Frog, which is the other member of the Teratohyla genus but is a lot larger, also differentiated by the lack of any spots on the Dwarf. An important reproductive characteristic of this species is that the egg clutches are left hanging from the underside of leafs, above a stream so that tadpoles can easily drop to a certain source of water.
Glass Frogs are fascinating, given their transparent ventral skin, which lets us peak into the internal structure of a frog. The organs that are visible varies according to the species, with some species showing the intestines and lower organs, while others show the heart and upper structure. In some of them, the bones are also visible inside the legs. Most of these frogs are overall green in coloration, which provides camouflage in the forest environment they live in.
This species is called Dusty given how the dorsal skin is covered in very small white spots. They are intermediate between the sizes of Strawberry and Green and Black Poison Dart Frogs, and definitely bigger than the Dwarf Glass Frog, which belongs to the same family of frogs. Their skin is mostly green, with yellowish tints in the ventral surfaces of the limbs and in the tips of fingers and toes. Given these colors, it is not surprising that one could be staring directly into one of these on a leaf and still not find it. The eyes are very large, located at each side of the head, enabling the frog to spot predators from both sides; the pupil is horizontally eliptical, while the iris is covered with an intricate pattern of blue and gray.
The Hourglass Tree Frog receives its name from the dark brown mark on its back, which resembles an hourglass in shape. Overall, it is colored orange and brown, with small light spots on darker areas and small dark spots on the lighter zones. Some individuals are rather patternless and look entirely orange. It is common and widespread in both caribbean and pacific lowlands. This species is arboreal and nocturnal, and can be found in disturbed areas, including gardens close to people’s homes. It is not likely to be confused with any other frog species that inhabit Costa Rica; the other two species in the Dendropsophus genus have a similar orange color, but without the intricate patterns of the Hourglass.
There are three Long-snouted Tree Frog species in Costa Rica, with the Boulenger’s and Olive being both widespread and common accross wet lowlands in the country, and the Dry Forest species being common in the northwestern region (Guanacaste). The Boulenger’s is mostly light brown, including the iris, with small patches of green and darker brown that provides better camouflage. It is colloquially known as “Rana Lagarto” (crocodile frog) in Costa Rica due to its unusually long snout.
It is arboreal and nocturnal, and males frequently call with their body upside-down during the wet season. To help hold this position, the innermost finger can be rotated up to 90 degrees, essentially pointing upwards, which provides a better grip on smooth surfaces like tree branches and trunks. The skin is granular, which might put off some people that feel that its appearance is gross. Yet amphibians have a very important role in wet ecosystems, as some of the insect prey they consume might develop into plagues if unchecked. Most amphibian species have been battling with declining populations, and protecting them from extinction is one of our biggest challenges.
The Common Ground-Dove is very similar to related species Ruddy and Plain-breasted Ground-Doves, however the Common is lighter in coloration, with a pink bill that is diagnostic; it also shows a scaled pattern in the throat and neck, which is missing from the other ground doves. Also similar to these species is the Inca Dove, which even behaves similarly as it forages most of the time on the ground, however the scaled appearance in the whole body should preclude any confusion. The male is ligher than the female, which looks grayish. All ground doves feature dark spots in the tips of primaries and secondaries, which look like a curved line when the wings are closed, although the Common’s should area spots are more numerous and do not form a line.
There are six species of Antshrikes that occur in Costa Rica, some more elusive than others, but all having a common theme: Their songs is heard more often than they are seen. All of them sing using a pattern of repeating notes that build more speed slowly, abruptly ending in a single note that usually is different from all others. The song of the Black-crowned Antshrike is very similar in pitch to the Barred Antshrike’s, so it is easy to confuse them. The Black-crowned is bigger and does not have the bold markings that the Barred has, only displaying small white dots and stripes on the wings, along a black crown which is difficult to see, given that they are usually perched higher than eye level inside the dark forest.
As a bird photographer, I strive for great image quality, but also value unique moments with rare or elusive species. This sighting of the Black-crowned Antshrike is one such encounter, a bird that can be easily identified by the song, but that can be difficult to see as they live in the dense, dark forest. To see them in the trail is priceless.