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
Handbook of the Birds of the World are large, measuring , and weighing between ; it has been commented in a review that "fork-lift truck book" would be a more appropriate title. As a complement to the "Handbook of the Birds of the World" and with the ultimate goal of disseminating knowledge about the world's avifauna, in 2002 Lynx Edicions started the Internet Bird Collection (IBC). It is a free-access, but not free-licensed, on-line audiovisual library of the world's birds with the aim of posting videos, photos and sound recordings showing a variety of biological aspects (e.g. subspecies, plumages, feeding, breeding, etc.) for every species. It is