The sun sets quickly in the tropics. Northern dwellers used to a gradual transition from day to night are often taken aback when daylight’s departure recalls a window being shut forcefully. This means there’s no time to prepare for the “night show” so to speak. As our eyes adjust to this new (and suddenly dark) world, our ears begin busily processing the sudden onset of a bizarre chorus of sound. This tropical nocturnal chorus is full of a rich assemblage of clicks, ticks, trills and shrills. While our first instincts might be to “let them be”, we may feel quite differently with a flashlight in hand. Then, our inner hunting instinct may take over and drive us to find the “faces behind the sounds”. As we ultimately find out, each strange sound may emanate from an equally strange denizen of the night.

Red-eyed Tree Frog in Costa Rica

One of the most ubiquitous sounds in Costa Rica’s lowlands and foothills is a serenely incessant “tinking.” The sound is so omnipresent that one would believe that enough searching will lead to discovering the sound’s maker. Laws of probability, however, perhaps don’t take into account how furtive this remarkable animal is. Maxing out at a whopping 21 millimetres for a full-grown adult is the Common Tink Frog, and most are much smaller. Like fellow nocturnal songsters – the crickets and katydids – tink frogs will immediately cease vocalizing precisely at the moment one is about to find it. In the lush rainforest foliage, there are also endless places to hide.

Though much less conspicuous in sound than the tink frog, the Red-eyed Tree Frog is more likely to be seen. Nonetheless, in a matter of seconds, they can transform from a visually loud, lanky amphibian to what looks like a green lump on a leaf. They are always a major target of night wanderings.

Common Potoo in Costa Rica

The value of a flashlight in tropical exploration is reaffirmed when a sweep through the rainforest understory reveals one of the many largely silent creatures. In addition to delicate tree snakes or docile tree boas, various possums cryptically lurk amidst thick foliage in search of fruit. Though not entirely silent, potoos are moth-eating birds that seem to embody the best of owls, whip-poor-wills and small mammals in a single idiosyncratic being. Watching them hunt by flashlight is sure to leave a lasting impression.

Central American Woolly Opossum

On our new Costa Rica tour next March, nocturnal exploration will be one of the signature experiences of the trip, especially at La Selva Biological Station in the Caribbean lowlands where nocturnal species richness is particularly high. Join us as we eagerly anticipate what this bewitching world has in store for our eyes and ears!