Todd-Carriker: Birds of Santa Marta Region, Colombia. 17 



self, replacing to a large extent the "dry forest" of the foothills. 

 Savannas are also found on the north slopes of the Sierra Nevada, 

 beginning at Pueblo Viejo on the Rio Ancha and extending upward 

 to the paramos, at least in the valleys of the watershed of this stream. 

 The presence of these savannas is rather puzzling, and has not hitherto 

 been satisfactorily explained. It is almost a certainty that where 

 such savannas occur, at least at points above 2,000 feet, and are in 

 an area obviously belonging to and surrounded by a forest belt, they 

 are due to artificial causes, deforestation and persistent burning over. 

 The fact that in regions of extensive savannas the humidity and pre- 

 cipitation is less, is an effect, rather than the cause of the formation 

 of the savannas, because the absence of forest lessens the atmospheric 

 condensation and thus diminishes the rainfall. 



Colombia is an old country, a fact often overlooked by authors and 

 travellers, and was settled before North America. Cutting of timber 

 and systematic burning covering a period of from one to three cen- 

 turies must inevitably have destroyed large areas of forest, while the 

 flora following in such cases would be the hardy grasses, which consti- 

 tute the vegetation of the savannas of today. Several instances tend- 

 ing to prove this theory have come under the observation of the junior 

 author within a period of only eight years, so that, if obvious results 

 can be obtained in that length of time, what might not have taken place 

 during one to three centuries? 5 



Mountain Forests. — The " dry forest " of the foothills gradually 

 and almost imperceptibly merges into the dense, cool, humid forest 

 of the higher altitudes, which with the exception of the areas of 

 savanna previously noted, covers everything between the altitudes of 

 2,000 to 3,000 feet upward to timber-line. At least this is true on the 

 Caribbean slope ; but according to Sievers the case on the whole south 



5 Sievers appears to lay much stress on the fact that the savanna appears 

 only on the south slopes, while the north slopes are wooded. This is only 

 added proof of my theory of the origin of these savannas, since it is a well- 

 known fact that the Indians always select the south slopes first for their cul- 

 tivations, as they get more sun at the time it is needed for the crops. This 

 same process is going on today, for the Indians of the Macotama Valley have 

 to go farther and farther each year to fell forest for their cultivations, as 

 under their primitive mode of agriculture the soil soon becomes unproductive, 

 and the land is burnt over every year when they burn the savannas to get fresh 

 new grass. — M. A. C, Jr. 



