Bohaiornithidae of sexual dimorphism, with the feathers being used by male members of a species for courtship display. A subadult specimen of an indeterminate bohaiornithid described in 2017 preserved feathers on various parts of the head and body which were analyzed and determined to have been iridescent in life. A referred adult specimen of "Bohaiornis" was preserved with a several rocks concentrated in the stomach region. Rocks in the stomach of birds and other animals are often believed to be gastroliths swallowed to assist in the digestion of plant material. However, the rocks apparently swallowed by this specimen are much larger,
Extracellular digestion initial components of the gastrointestinal tract are the mouth and the pharynx, which is the common passage of the oral and nasal cavities. The pharynx leads to the esophagus, a muscular tube that delivers food to the stomach, where some preliminary digestion occurs; here, the digestion is extracellular. From the stomach, food passes to the small intestine, where a battery of digestive enzymes continue the digestive process. The products of digestion are absorbed across the wall of the intestine into the bloodstream. What remains is emptied into the large intestine, where some of the remaining water and minerals are absorbed;