Most vertebrates have gallbladders, but the form and arrangement of the bile ducts may vary considerably. ... Several species of mammals (including horses, deer, rats, and laminoids), several species of birds (such as pigeons and some psittacine species), lampreys and all invertebrates do not have a gallbladder .

Do pigeons have a gallbladder?

Pigeons lack a gallbladder, but also have two extrahepatic ducts similar to those of quails. However, the hepatic-enteric duct opens solely to the descending part of the duodenum close to the stomach.

Where is a birds gallbladder?

The avian gallbladder is attached to the liver lobe and can be easily examined by moving the liver to one side. This sacklike structure is greenish-black in color due to the bile present in it. The trachea and syrinx (voice box) are visible at the base of the heart.