The digestive system of birds includes an esophagus, crop, stomach with two regions (proventriculus and ventriculus), intestine, and cloaca. The crop acts as a storage organ that allows birds to quickly ingest large amounts of food and digest it later. In pigeons, the crop produces "pigeon's milk" which young pigeons feed on. The stomach contains the proventriculus, which secretes gastric juices, and the ventriculus or gizzard, which has muscular walls to crush hard materials like seeds. The intestine absorbs nutrients with help from the pancreas and liver. The cloaca is the last part and acts as a common opening for waste elimination and the reproductive system

1. DIGESTIVE SYSTEM IN BIRDS
1. ESOPHAGUS
2. CROP.
3. STOMACH.
(proventriculus)
4. GIZZARD.(Ventriculus)
5. INTESTINE.
6. CLOACA

2. CROP IN BIRDS
• Crop is present in many birds. Crop is a diverticulum of the
esophagus. It is a storage structure. It allows birds to quickly ingest
large quantity of food. Then they move to save places and digest
the food.

3. CROP OF PIGEON
• The crop of pigeons produces “pigeon’s milk.”
• Pigeon’s milk, is a cheesy secretion. It is formed by the proliferation and
sloughing of the lining or the crop Young pigeons feed on pigeon’s milk till
they are able to eat grain. Vultures and birds of prey also use their esophagus
for storage. The insectivorous birds feed throughout the day. Therefore, crop
is less developed in them.

4. STOMACH OF BIRDS
• The stomach of birds has two regions. These regions are proventriculus and
ventriculus.
• (a) Proventriculus: It secretes gastric juices. Gastric juice initiates digestion.
• (b) Ventriculus or (gizzard): It has muscular walls to crush the seeds and other hard
materials. Birds swallow, sand and stone in gizzard. These stones help in digestion

5. INTESTINE IN BIRDS
Intestine
• Most of digestion and absorption occurs in the small intestine. Intestine
receives secretions from the pancreas and liver. These secretions help in
digestion. Paired ceca are
• Present at the union of the large and small intestine. Ceca are blind-ending
sacs. They contain bacteria. These bacteria help in the digestion of cellulose.

6. CLOACA
Cloaca
• It is the last part of digestive system
• Cloaca is common opening for urinogenital duct and anus.
• Both male & female have cloaca. Cloaca is an internal opening, a bird’s sex
organ, testes or ovaries discharge sperm or egg. It also eliminates undigested
food.