The Variety and Nutritional Value of Foods Consumed by Hawaiian Crow Nestlings, an Endangered Species

Research was conducted to determine the food habits of Hawaiian Crow (Corvus hawaiiensis) nestlings, variety of food items ingested relative to their age, and the nutritional composition of ingested fruits. Knowledge of the fruits’ nutritive value and the nestlings’ diet allowed us to determine what plants best meet nutritional needs of adult and nestling crows for restocking purposes. Our evaluation of fecal droppings suggested that nestlings were fed a variety of items similar to those ingested by adults. The types and proportions of food materials found in droppings changed with age. Crow nestlings’ consumption of olapa (Cheirodendron trigynum) and oha-kepau (Clermontia spp.) fruits, passerine nestlings, and a variety of arthropods made up the highest percentage of food items found in droppings. Food items eaten by Hawaiian Crow nestlings generally had a high water content but varied greatly in nutrient density. Crude protein ranged from 1.81% in the hoawa (Pittosporum hosmeri) seed shell to 16.32% in the aiea (Nothocestrum longifolium) fruit. Fat content, gross energy content, fiber fractions, total digestible nutrients, digestible energy, metabolizable energy, and mineral levels varied greatly among fruit types. In general, the higher the fat content, the higher the energy density, and the lower the fiber fraction.