Egestion of chitin in pellets of American Kestrels and Eastern Screech Owls

In studying the digestibility of chitin by American Kestrels (Falco sparverius) and Eastern Screech Owls (Otus asio). we found portions of ingested chitin not only occurred in excreta but also pellets. When commercial chitin was fed in turkey or chicken meat, 23.8% (American Kestrel) and 29.6% (Eastern Screech Owl) of the ingested chitin was egested in pellets. In American Kestrels, 59.2% of the total amount of ingested chitin was found in excreta. The percent of chitin egested as pellets as compared to the amount ingested showed a negative correlation (r = -0.76, P < 0.001). Our results suggest that the lower gastrointestinal tract contributes to total chitin digestion in American Kestrels.