COSTA RICA. 37 
country is extensively wooded, the forests consisting of trees of all sizes, many of them 
attaining enormous girth and height, especially on the eastern slope, where the rainfall 
is most abundant; consequently, vegetation is there much denser and penetration very 
difficult. On the Pacific side the forests have less undergrowth, the trees are larger 
and taller, and progress through them is comparatively easy. ‘There is, however, an 
exception in the Guanacaste region in the Nicoya peninsula, where great tracts of 
erass lands or savannas, with scattered patches of woodland prevail. Trees with 
berries and other kinds of fruit abound at all altitudes, furnishing food throughout 
the year for the multitudes of tanagers, finches, parrots, toucans, and trogons, while 
their blossoms give sustenance to innumerable humming-birds. The tree which, 
throughout the tropics, mostly attracts other birds is one of the Leguminose, 
bearing biennially great masses of fragrant tassel-like blossoms which persist for some 
days before fading, while the season of flowering extends over a period of more 
than two months; it is known as the ‘guava’ (this is not, however, the guayava of 
commerce). 
On the Caribbean slope the rainfall is fairly continuous during the whole year, reach- 
ing on an average from 200 to 230 inches on the lower land. ‘The greatest rainfall is 
from the middle of December to the middle of January, and again from the middle of 
June to the middle of August, while from January 15th to March Loth it is fairly dry 
and cool, and this season on the eastern slope is delightful. In the high regions the 
rainfall is less, and there are alternately six months of wet and dry season. During 
the first and last months of the rainy season the fall is slight and rarely of daily 
occurrence, while in July, August, and October it rains every afternoon, and often 
violently. During the dry season high winds prevail at all altitudes, but little if any 
wind blows during the wet season. Influenced by the constant rain, the vegetation is 
most luxuriant, and with it we find animal life consequently much more abundant. 
So numerous are the species that probably not less than three hundred and ninety 
land and fresh-water birds may be found on the lower portion of the Caribbean slope 
up to 3000 feet. The high peaks rising above the regions of the Central plateau 
constitute quite a distinct life zone. The main range of mountains extends from the 
extreme north-west to the eastern central portion, gradually increasing in height and 
ending in a chain of volcanoes reaching an altitude of from 8000 to 11,000 feet, 
including Poas, Barba, Irazu, and Turrialba. Here there is a break formed by two 
deep, broad valleys, the river Reventazon flowing in the one to the Atlantic and the 
Rio Grande de arcoles in the other to the Pacific; their sources are within half a 
mile of each other, the ‘divide’ or watershed being known as ‘ El Alto’ and having 
an elevation of 5000 feet. The whole country to the south is an unbroken mass of 
mountains containing but few inhabitants except the rapidly diminishing Indians. 
Mr. Carriker (Ann. Carnegie Museum, vi. 1910) considers that the Avifauna of 
Costa Rica is composed of three primal groups—the Boreal, the Sonoran, and the 
