the two rivers and are composed primarily of utisols. Temperature variation is slight year round, and daily temperatures can fluctuate from . As the climate is tropical wet, rain is common throughout the year, and the average annual rainfall is 4 meters (13 feet). The rainiest months are July, November, and December, while the least rainy season is from February to April. The dry season is rarely long or severe. Flora and fauna La Selva's biological resources are rich and largely intact which generates high biological diversity and productivity. The reserve is home to a wide range of wildlife, including large predators, rare birds, and an astonishing number of invertebrates. It is estimated that La Selva contains over 500,000 species, with more than half (about 300,000) consisting of insect species. Plants Four major tropical life zones are protected between the La Selva and its connection to Braulio Carrillo National Park. Within this reserve, more than 5,000 species of vascular plants can be found, of which more than 700 species are trees. La Selva hosts a large variety of epiphytes, epiphylls, and many climbing aroids. Other common tree species include Welfia regia, Socratea exorrhiza, and most notably Pentaclethra macroloba, which occur in an unusual abundance. Mammals There are many mammalian species including large predators such as jaguars (Jaguar) and pumas (Puma (genus)). According to the OTS Website , five of the six species of felines in the country are found within the reserve. Some other species include the collared peccary (Tayassu tajacu) and Hoffmann's two-toed sloth (Choloepus hoffmanni). Birds The large number of bird species found here exceeds any other site in Central America. The most recent list published includes 467 species of birds. When taking into account the total number of species found one must understand that many are rare or may have been seen by mistake. Of these species, more than half breed locally, and many are altitudinal migrants or North American overwintering migrants. Several ecological variables influence the vulnerability to habitat fragmentation, and other changes in the environment, in various groups of avifauna: diet, habitat, propensity to join mixed-species flocks, and nest type. Insectivorous birds are particularly sensitive to fragmentation, perhaps due to their dietary or foraging substrate specialization; forest under-story birds are most vulnerable to changes in their habitat; mixed-species flocks are especially sensitive to fragmentation as they typically roam over large areas; and certain nest types