Digestion a thin-walled expanded portion of the alimentary tract used for the storage of food prior to digestion. In some birds it is an expanded, muscular pouch near the gullet or throat. In adult doves and pigeons, the crop can produce crop milk to feed newly hatched birds. Certain insects may have a crop or enlarged esophagus. Herbivores have evolved cecums (or an abomasum in the case of ruminants). Ruminants have a fore-stomach with four chambers. These are the rumen, reticulum, omasum, and abomasum. In the first two chambers, the rumen and the reticulum, the food is mixed with saliva and
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