Corcovado: Voices of the Lowland Rainforest
by: David L. Ross, Jr.  (what's this?)

 Beneath towering Pacific clouds a rolling surf laps the shore of southwestern Costa Rica's Osa Peninsula, wetting the toes of the largest tropical rainforest in all of Central America's western slope. From this white sand and rock strewn shoreline to the cloud-brushed peaks on the eastern horizon stands the tallest and best-developed rainforest in all of Central America, rivaling in height its tallest counterparts in Malaysia and Amazonia (Hartshorne 1983). This is Corcovado National Park, bathed in equatorial sunshine and receiving near 500cm(200inches) of rainfall annually. Its boundaries protecting 41,788 hectares (103,216 acres) include many distinct habitats ranging from fresh water lagoon and swamp to cloud forest.

   Contained within this tropical wilderness is an immense biodiversity. Braced by impressive wall-like buttresses fanning outward across a darkly shaded forest floor, centuries old rainforest giants stretch skyward upon massive trunks wrapped in woody vines and leafy climbers. In the lowlands, stands of Giant Cashew trees (Anacardium excelsum) and (Caryocar costaricencis) impart a cathedral-like magnificence. It is a forest with tree species numbering in the hundreds, characterized by a dense canopy hung with epiphytes and draped with lianas.

   Unobstructed views of the rainforest skies are uncommon away from the field station clearing and river edges. Dense foliage and a multi-layered canopy further hinder visibility within the forest. Through the millennia the inhabitants have developed a reliance upon vocalizations and acoustic signals for communication within the depths of the dimly lit realm. Indeed many of the most haunting and evocative sounds to be experienced on this planet are to be encountered within such rainforests. Whether it be the eerie tremulous whistles of tinamous at dusk, the drawn-out rasping calls of a Scarlet Macaw pair flying to roost, or the ringing cacophony of Gray-necked Wood-rails duetting from a creek bed before dawn, few of us can not take notice.

   While the lowlands of Corcovado do provide excellent and ample opportunity to view rainforest inhabitants, one will only see the smallest percentage of what is so evident audibly. Thus it is often through the continuous symphony of sounds so characteristic of the tropical lowlands, that the diversity and shear numbers of animals are best revealed. This continuum of vocalizations and utterances from the dark greens of magnificent forest embodies the very essence of the rainforest experience.


Beach near Rio Sirena Field Station, image 2, Giant Ceiba Tree in forest near the Corcovado Basin
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