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In a bird's digestive system, the crop is an expanded, muscular pouch near the gullet or throat. It is a part of the digestive tract, essentially an enlarged part of the esophagus. As with most other organisms that have a crop, it is used to temporarily store food. Not all bird species have one.
A bird swallows small bits of gravel that act as 'teeth' in the gizzard, breaking down hard food such as seeds and thus helping digestion. [4] These stones are called gizzard stones or gastroliths and usually become round and smooth from the polishing action in the animal's stomach. When too smooth to do their required work, they may be ...
Bird anatomy, or the physiological structure of birds' bodies, shows many unique adaptations, mostly aiding flight.Birds have a light skeletal system and light but powerful musculature which, along with circulatory and respiratory systems capable of very high metabolic rates and oxygen supply, permit the bird to fly.
Birds' diets are varied and often include nectar, fruit, plants, seeds, carrion, and various small animals, including other birds. [77] The digestive system of birds is unique, with a crop for storage and a gizzard that contains swallowed stones for grinding food to compensate for the lack of teeth. [ 149 ]
Fish have what is often described as a two-chambered heart, [43] consisting of one atrium to receive blood and one ventricle to pump it, [44] in contrast to three chambers (two atria, one ventricle) of amphibian and most reptile hearts and four chambers (two atria, two ventricles) of mammal and bird hearts. [43] However, the fish heart has ...
In addition to bony fish and cephalopods, macrolecithal eggs are found in cartilaginous fish, reptiles, birds and monotreme mammals. [3] The eggs of the coelacanths can reach a size of 9 cm (3.5 in) in diameter, and the young go through full development while in the uterus , living on the copious yolk.
Bird ringing is the term used in the UK and in some other parts of Europe, while the term bird banding is more often used in the U.S. and Australia. [49] bird strike The impact of a bird or birds with an airplane in flight. [50] body down The layer of small, fluffy down feathers that lie underneath the outer contour feathers on a bird's body. [51]
The shape of the beak, which correlates with dietary habits, is important in determining how a bird can crack the seed coat and obtain the meat of the seed. [2] Black-oil sunflower seeds attract the widest variety of birds [3] and are commonly used in backyard bird feeders. [4] Using a variety of seeds can help attract specific types of birds ...