Abstract
This study aimed to explain and compare the anatomical, histological, histochemical & histomorphometric analyses of the syrinx in different species of birds. This study includes 21 healthy birds from geese (Anser Anser Domesticus), cattle egrets (Bublucus ibis) & house sparrows (Passer domesticus), seven from each species. Results: Anatomically, the syrinx of the three studied species was tracheobronchial type composed of 2 different cartilaginous groups arranged in three parts: Tracheo-Syringeal cartilage in (cranial, intermediate part (tympanum)) and broncho-syringeal cartilage; as well as the trachea's muscles were once thought to be the syrinx's extrinsic muscles. Histologically, the lamina epithelialis of the Tracheo-Syringeal part was represented by pseudostratified ciliated columnar epithelium in the three investigated species with goblet cells in geese, house sparrows and lack goblet cells in cattle egrets. The pessulus in all three investigated species was triangular and positioned at the tip of the tracheal bifurcation. The bulla of house sparrow was considered the intrinsic syringeal muscles and these muscles in sparrows are not only present in geese or cattle egrets.

Key words: KEYWORDS: Macro- Micro-morphological, syrinx.