, a large taxon that includes aerial insectivores, such as the Common Nighthawk (Chordeiles minor), is one of the least studied avian clades worldwide due to the nocturnal and crepuscular nature of its member species (Cleere, 1998).
The avian retina is anangiotic (no visible blood vessels) and generally believed to be atapetal (except in Caprimulgiformes
Osteologia craniana de Nyctibiidae (Aves, Caprimulgiformes
: Chordeilis acutipennis, el "chotacabras trinador"es comun, de costumbres crepusculares y nocturnas, forma grupos al atardecer, especialmente en verano.
In our study, the common carotid artery gave off the vertebral trunk in the sparrowhawk as in the long-legged buzzard (Erdogan & Kilinc), the Eurasian bittern (Erdogan) and some bird families such as Coliiformes (Glenny, 1944), Gaviiformes (Glenny, 1945), Charadriiformes (Glenny, 1947), Caprimulgiformes
(Glenny, 1953a) and Ciconiiformes (Glenny, 1953b).
Order Passeriformes was dominating with 57% species followed by Anseriformes (7%), Charadriiformes and Accipitriformes (6%) each, Columbiformes (5%), Galliformes and Falconiformes (4%) each, Pelecaniformes (3%), Coraciiformes and Gruiformes (2%) each, and Bucerotiformes, Apodiformes, Caprimulgiformes
, Piciformes, Suliformes and Strigiformes (1%) each.