page_title: Confuciusornis
section_title: Diet
hierarchical_section_title: Confuciusornis / Paleobiology / Diet
caption_attribution_description: English: Tawny Frogmouth (Podargus strigoides) in Blackbutt Reserve, Newcastle, Australia
context_page_description: Confuciusornis is a genus of primitive crow-sized avialan from the Early Cretaceous Period of the Yixian and Jiufotang Formations of China, dating from 125 to 120 million years ago. Like modern birds, Confuciusornis had a toothless beak, but close relatives of modern birds such as Hesperornis and Ichthyornis were toothed, indicating that the loss of teeth occurred convergently in Confuciusornis and living birds. It is the oldest known bird to have a beak. It was named after the Chinese moral philosopher Confucius. Confuciusornis is one of the most abundant vertebrates found in the Yixian Formation, and several hundred complete, articulated specimens have been found.
context_section_description: In 1999, Chinese paleontologist Lianhai Hou and colleagues suggested that Confuciusornis was likely herbivorous, though no stomach contents were yet known, pointing out that the beak curved upwards and was not raptorial. Paleontologists Dieter S. Peters and Ji Qiang hypothesized in 1999 that, although no remains of toe webs have been conserved, it caught its prey swimming using its rather soft bill to search for prey below the waterline. Several extant bird species have been presented as modern analogues of Confuciusornis providing insight into its possible lifestyle. Peters thought that it could be best compared with the white-tailed tropicbird (Phaeton lepturus), a fisher that too has a long tail and narrow wings—and even often nests in the neighbourhood of volcanoes.
  Polish paleontologist Andrzej Elżanowski found it unlikely in 2002 that a long-winged and short-legged bird like Confuciusornis would forage in tree crowns, and instead proposed that it foraged on the wing, seizing prey from the water or ground surface. Indications for this included the combination of long wings that appear adapted for soaring, leg proportions (long femur, short foot) that are similar to those of frigate birds and kingfishers, and occipital foramen that opened at the back, a toothless beak similar to but shorter than that of kookaburras, and the absence of specializations for swimming. He conceded that Confuciusornis may have been able to swim, as it possibly foraged over water.
  In 2003 Chinese paleontologists Zhonghe Zhou and Fucheng Zhang stated that though nothing was known about its diet, its  robust and toothless jaws suggested it could have fed on seeds, and noted Jeholornis preserved direct evidence of such a diet.
  In 2006, Johan Dalsätt and colleagues described reported a C. sanctus specimen (IVPP V13313) from the Jiufotang Beds which preserves seven to nine vertebrae and several ribs of a small fish, probably Jinanichthys. These fish bones are formed into a tight cluster about 6 mm (0.24 in) across, and the cluster is in contact with the seventh and eighth cervical vertebrae of the bird. The condition of the fish indicates it was about to be regurgitated as a pellet, or that it was stored in the crop. No other fish remains are present in the slab. Though it is unknown how common fish were in the diet of Confuciusornis, the finding did not support a herbivorous diet, and the researchers pointed out that no specimens have been found with gastroliths (stomach stones), which are swallowed by birds to help digest plant fibers. Instead, they suggested it would have been omnivorous, similar to for example crows.
  Andrei Zinoviev assumed it caught fish on the wing.
  The skull was relatively immobile, incapable of the kinesis of modern birds that can raise the snout relative to the back of the skull. This immobility was caused by the presence of a triradiate postorbital separating the eye socket from the lower temporal opening, as with more basal theropod dinosaurs, and the premaxillae of the snout reaching all the way to the frontals, forcing the nasals to the sides of the snout.
caption: Sally-striking birds with broad gapes and large jaws, such as the tawny frogmouth, may be the closest modern analogues to Confuciusornis
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