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
Hawking (birds) for certain kinds of aerial insect as a food source seems to correlate with gregarious or colonial behavior versus territoriality. For birds that take advantage of swarming insects, which are by nature found in local concentrations, colonial breeding can be a successful strategy. An example is the cliff swallow of western North America. Its relative the barn swallow hunts larger, non-swarming insects, and is more solitary. Certain neotropical tyrant flycatchers will join mixed-species foraging flocks, as will some Asian drongos. Such flocks stir up flying insects, which can then be picked off in quick sallies. Hawking (birds) Hawking is a