Bird anatomy Birds have a four-chambered heart, in common with mammals, and some reptiles (mainly the crocodilia). This adaptation allows for an efficient nutrient and oxygen transport throughout the body, providing birds with energy to fly and maintain high levels of activity. A ruby-throated hummingbird's heart beats up to 1200 times per minute (about 20 beats per second). Many birds possess a muscular pouch along the esophagus called a crop. The crop functions to both soften food and regulate its flow through the system by storing it temporarily. The size and shape of the crop is quite variable among the birds. Members
Birds of the Amazon the Amazon rainforest is able to provide a home to thousands of birds with different survival needs. Amazonia is commonly dived into eight areas of endemism (districts): Napo, Imeri, Guiana, Inambari, Rondonia, Tapahos, Xingu and Belem. Although each area is similar in ecological characteristics, their biotas were assembled differently. With the progressive destruction of the rainforest comes a loss of habitats for many species of birds. As of today, over twenty percent of the original Amazon rainforest is gone, mostly as a result of deforestation and human encroachment. Human-made clearing has had important effects on bird species. Two to four