Crop (anatomy) Crop (anatomy) A crop (sometimes also called a croup or a craw, or ingluvies) is a thin-walled expanded portion of the alimentary tract used for the storage of food prior to digestion. This anatomical structure is found in a wide variety of animals. It has been found in birds, and in invertebrate animals including gastropods (snails and slugs), earthworms, leeches, and insects. Cropping is used by bees to temporarily store nectar of flowers. When bees "suck" nectar, it is stored in their crops. In a bird's digestive system, the crop is an expanded, muscular pouch near the gullet or throat.
Birds of the Danube Delta and especially of feeding the deltaic biotopes are providing in the warm season of the year. This phenomenon is also supported by the presence – in different deltaic biotopes as against the common ones – of some species, which in the rest of their area cover other life environments. The species of non-brooding deltaic birds were classified into the biotopes they visit while resting on the Danube Delta's territory and they are connected to by the way these biotopes are providing their food. The ornithological biotopes of the Danube Delta belong to three well-individualized habitats, namely the aquatic, the amphibian