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 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 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.
The Heliomaster genus contains four species, two of which occur in Costa Rica, including the Long-billed Starthroat that can be spotted in the Caribbean and northern lowlands, as well as in the south Pacific. It also includes the Plain-capped Starthroat, which is mostly seen in the north Pacific, central valley and some valleys in the south Pacific.
Both Starthroats have longer than average bills which are straight, although both species have similar bills. The main difference between the Long-billed and Plain-capped is that the former displays a colorful blue-green forecrown, while the latter lacks that crown. To aid in identification, it can be noted that the Long-billed has a postocular spot, while the Plain-capped has a postocular strip. Other than those two specific traits, the two species are very similar, with olive upperparts and gray to white underparts, and a magenta throat that is iridescent. The tips of the tail feathers are white, which can be seen the most dramatically during flight.
Purple Gallinules are some of the most brightly colored birds that you can see walking in Costa Rica. Indeed while they can also fly, they more commonly wade in shallow waters and in dense grass plains, looking for prey. I have seen them in Palo Verde in big numbers, and spotted individuals in Rio Frio, where they join chickens and forage in the backyards of houses; indeed I was able to see two adults rearing four young hatchlings, which were still covered in black fluffy hairs, getting along with the chickens just fine. The underside and head is entirely purple with a metallic look, showing a small light blue patch on the forehead. The beak is mostly bright red, with a yellow tip. The upperparts show blue to olive green hues, particularly on the wings. The yellow legs are long, letting them to wade in shallow edges of lagoons without having to swim.
Green Iguanas are the biggest species of lizards in the world, reaching lengths up to 1.5 meters including the tail. They are abundant in Costa Rican lowlands, and can be found in most of America’s continent, either naturally occurring or as established populations of escaped pets, as they are a very frequent target among pet lovers. They can be found in many beaches, around rivers, high in the tree canopy or walking slowly on the grass. Their diet is composed mostly of leaves, flowers and fruits, although some individuals have been observed eating insects and rodents.
Green Iguanas are not necessarily green in color, instead they have a lot of variability in their range. In some areas they are green, others brown or red, even blue in Peru. The back of the male is covered with spines, a defense mechanism to keep predators at bay, and they feature a dewlap, which is a fold of skin that starts at the front of the lower jaw and ends at the junction where the front limbs start. The dewlap is normally hanging, although it can be displayed as a sign of aggression.
The Pug-nosed Anole is a small, slender lizard with a green body and a conspicuous black line that runs from the lower jaw through the eye and to the top of the head. The iris is orange with a black, round pupil. They are active during the day and sleep during the night. The individual below was seen in Yorkin near the frontier with Panama, where it stayed motionless for more than half an hour, while we illuminated it with lamps and took pictures from close distances.
The Green Basilisk, also known as the Jesus Christ Basilisk due to its incredible feat to run on water, is one of the four species of the Basiliscus genus and of three species to occur in Costa Rica. The similar Striped Basilisk is brown with two yellow lines that run one through they, and a thicker one from below the eye, both ending in the upper portions of the back.
The male has a big crest that protudes both on the head, back and tail, which can be raised to signal that it is angry or defending its territory. Most of its body is green with light blue spots around the back, a color pattern that lets it camouflage very easily in foliage and vegetation, particularly during the morning when they bask in the sun to warm up their bodies. The female shows a lighter shade of green than the male. Their eyes are bright yellow. Both their fingers and toes are very large, with scales that can be extended, increasing the effective surface area of their feet and enabling them to run over water for short distances, up to 20 meters.