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 treetops. At its current rate of destruction, the rainforest will be gone in forty years. Human encroachment also negatively affects the habitat of many Amazonian birds. Agriculture and road clearings limits the habitable areas. Birds in the Amazon are distinguished by which layer of the rainforest they reside in. Each layer or community has unique plants, animals and ecosystems. Birds interact with other animals in their community through the food chain, competition, mating, altruism and symbiosis. The Amazon rainforest has four layers, each of which has its own unique ecosystem. The top layer is the emergent (or dominants) where