Emerald Glass Frog (Espadarana prosoblepon)

We found this frog during a night time hike in search of the Ghost Glass Frog at Yatama Ecolodge. It acted very docile, barely moving its head down from its upward position. The easiest way to recognize it among the Glass Frog family is by the dark spots on an otherwise uniform green skin. Males feature a blue-green hook, seemingly at the shoulder joint as in the left-hand side picture below; one can only ask what purpose this structure it might serve. The eyes are relatively forward facing, like in most other species in the family.

Coppery-headed Emerald (Elvira cupreiceps)

The Coppery-headed Emerald is one of the few species of birds that are true endemics of Costa Rica, meaning only found in this country. The male is mostly green, with the copper hues on the head that can only be seen in the appropriate light and angle. The female has grey underparts and lacks the copper colors on the head. Both have a black downcurved bill, which help with identification versus similar species like the Rufous-tailed Hummingbird, with which it shares the brownish-red rump. They are one of the tiniest species of hummingbirds in Costa Rica. They are seen in the mid to high elevations, in places where there is high humidity, but specially in the Cinchona and Vara Blanca zone.

Violet-tailed Sylph (Aglaiocercus coelestis)

The Violet-tailed Sylph is part of the Aglaiocercus genus, containing two more species, one of them being the Long-tailed Sylph which we also saw in Colombia during our trip. It has a long tail that glows in purple from the back. Other than that, the bird is mostly green, with flashes of orange on the belly and blue hues on the back. Their bill is relatively short when compared with other hummingbird species on its range. When the outer tail feathers are molted, individuals can be seen with shorter tails, like in the pictures below, since those feathers are precisely the ones that grow very long.

Tyrian Metaltail (Metallura tyrianthina)

Metallura is a genus that contains nine species, all of them inhabiting different ranges in the Andes mountains. They are small and vary in coloration of the plumage. The Tyrian Metaltail is green overall, showing a white postocular spot, and white plumage on the belly and vent that gives it a scaled pattern on the underparts. The gorget is metallic green, however it is not seen from every angle due to iridescence. We saw one individual in Rio Blanco Natural Reserve, perched on a small ornamental plant, most probably resting after a full nectar meal.

Andean Emerald (Amazilia franciae)

This is a medium-sized hummingbird that can be found in South America, specifically in Colombia, Ecuador and Peru. Males have a violet crown, while females have a green crown. It has iridescent plumage, like many other hummer species, which changes the color depending on the view angle and the angle of the light that bounces off it, giving away colors that look metallic and intense. In general it is green on the back and sides, white on the belly, chest and throat, and coppery in the upper tail. The bill is black, mostly straight and thin. The wings are brown, but glow blue when iridescent.