Chances are you’ll have read much about Corcovado’s unparalleled biodiversity before your arrival, but that does little to prepare you for the sheer scope of it when you step into the park. Suffice it to say, there is much to feast your eyes on in Corcovado.
Plants and trees
Walking through Corcovado you’ll see many lianas, vines, mosses and spectacularly tall trees – some of them 50 or 60m high, and a few more than 80m high. All in all, Corcovado’s area is home to about a quarter of all the tree species in the country, including the silkwood (or ceiba pentandra), characterized by its height – thought to be the largest tree in Central America – and its smooth grey bark. One silkwood, near the Llorona–San Pedrillo section of the trail, is over 80m high and 3m in diameter. You’ll also notice huge buttresses: above-ground roots shot out by the silkwoods and other tall canopy species. These are used to help anchor the massive tree in thin tropical soil, where drainage is particularly poor.
Corcovado supports a higher volume of large mammals than most other areas of the country, except perhaps the wild and rugged Talamancas. Jaguars need more than 100 square kilometres each for their hunting; if you are a good tracker you may be able to spot their traces within the park, especially in the fresh mud along trails and riverbeds. Initially they look identical to those made by a large dog, but the four toes are of unequal size (the outermost one is the smallest) and the fore footprint should be wider than its length. You might, too, see the margay, a spotted wildcat about the size of a large domesticated house cat, which comes down from the forest to sun itself on rocks at midday. The ocelot, a larger spotted cat, is even shyer, rarely seen for more than a second, poking its head out of the dense cover and then melting away into the forest again immediately.
With a body shape somewhere between a large pig and a cow, the Baird’s tapir is an odd-looking animal, most immediately recognizable for its funny-looking snout, a truncated elephant-type trunk. Tapirs are very shy – and have been made even more so through large-scale hunting – though you stand a reasonable chance of spotting one crossing the clearing at Sirena’s airfield. More threatening are the packs of white-collared peccaries, a type of wild pig, who in Corcovado typically group themselves in packs of about thirty. They are often seen along the trails and should be treated with caution, since they can bite you. The accepted wisdom is to climb a tree if they come at you threateningly, clacking their jaws and growling, though this, of course, means you have to be good at climbing trees, some of which have painful spines.
More common mammals that you’ll likely spot are the ubiquitous agouti, foraging in the underbrush. Essentially a large rodent with smooth, glossy hair, the agouti looks similar to a large squirrel. The coati, a member of the raccoon family, with a long ringed tail, is also sure to cross your path. Another mammal found in significant numbers in the park – and all over the peninsula – is the tayra (tolumuco), a small and swift mink-like creature. They will in most cases run from you, but should not be approached, as they have teeth and can be aggressive.
Among Corcovado’s resident birds is the scarlet macaw, around 300 of which live in the park – more, in terms of birds per square kilometre, than anywhere else in the country. Macaws are highly prized as caged birds and, despite the efforts of the SPN, poaching is still a problem here, as their (relative) abundance makes them easy prey. Around the Río Sirena estuary, especially, keep an eye out for the boat-billed heron, whose wide bill gives it a lopsided quality. The big black king vulture can also be found in Corcovado; a forager rather than a hunter, it nevertheless looks quite ominous. There are many other smaller birds in Corcovado including, perhaps, the fluffy-headed harpy eagle. Though the harpy is thought to be extinct in Costa Rica, ornithologists reckon there’s a chance that a few pairs still live in Corcovado, and in the Parque Internacional La Amistad on the Talamanca coast.