Assimilation efficiency of the Red-winged Starling Onychognathus morio fed Strelitzia nicolai arils

There is a paucity of studies investigating the digestive efficiencies of avian frugivores fed fibrous (also referred to as woolly) aril pulp. We fed whole Strelitzia nicolai seeds with arils to captive Red-winged Starlings (Onychognathus morio) to determine daily food and energy intake, digestive transit time and assimilation efficiency. Strelitzia nicolai arils were found to contain a remarkably high lipid content (66.78 %), with a correspondingly low water (7.61 %) and protein (5.79 %) content. Birds generally ate only the aril of S. nicolai seeds, but if they swallowed the seeds whole then they either defecated or regurgitated the seeds without the aril. Red-winged Starlings were found to have fast digestive transit times (approx. 24 min) and very high apparent assimilation efficiencies (approx. 96 %) of the aril of S. nicolai seeds.