Raptor Gastrointestinal Anatomy and Physiology

Key Points

  • The raptor bill plays a role in prehension and sometimes killing. Food is torn from the carcass by the sharp cutting edges or tomia of the bill in Falconidae (falcons and caracaras); owls often gulp down prey whole.
  • The tongue has a barbed surface, allowing greater manipulation of food.
  • The esophagus is strong and distensible.
  • Most diurnal birds of prey possess a well-developed crop or ingluvies.
  • Owls lack a true crop and instead there is a fusiform enlargement or widening of the esophagus.
  • The stomach is thin-walled and muscular, adapted more for storage than grinding. The proventriculus is relatively large and highly distensible. The ventriculus is often smaller and sac-like.
  • Ceca are small, vestigial or absent in diurnal birds of prey, but large and well developed in strigiforms.
  • The gastroduodenal contraction sequence in raptors is much simpler than that described in granivores. Peristaltic waves move directly from the proventriculus, through the isthmus, into the ventricles, and finally pass into the duodenum.
  • A pellet is a compacted mass of indigestible material such as fur, feathers, grains, bones, teeth, and claws.
  • The final phase of gastric digestion in the raptor involves pellet formation within the ventriculus and egestion, also known as “casting”.

Raptors are a diverse group of birds consisting of order Strigiformes or owls and diurnal birds of prey such as falcons, hawks, and eagles. Order Falconiformes, traditionally considered a broadly defined, polyphyletic group, has recently been divided into two orders with only family Falconidae (falcons and caracaras) remaining in Falconiformes. Other diurnal raptors belong to order Accipitriformes . . .

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Further reading

Balgooyen TG. Pellet regurgitation by captive sparrow hawks (Falco sparverius). Condor 1971;73:382-385.

Chaplin SB. Effect of cecectomy on water and nutrient absorption of birds. J Exp Zool Suppl 3:81-86, 1989.

To cite this page:

Pollock C. Raptor Gastrointestinal Anatomy and Physiology. March 6, 2016. LafeberVet Web site. Available at https://lafeber.com/vet/raptor-gastrointestinal-anatomy-physiology/