Feeding ecology and nutrition of Australian lorikeets

Abstract

Nutritional adequacy is imperative to maintain health and optimize reproductive output of lorikeets. Although lorikeets feed primarily on nectar and pollen, substitution with simple sugars and a high protein diet is inadequate. Although nectar consists primarily of sucrose, the highly indigestible raffinose sugars contained in some plant and insect exudates may promote colonization of beneficial bacteria such as the bifidobacteria, decreasing clostridial populations and possibly influencing infections of eggs with Salmonella enteritidis. Protein content of wild fruits is marginally higher when compared with commercially available fruits commonly fed to birds but fat content of wild fruits can be as high as 29%. Wild figs also have higher fat and calcium content than their domesticated counterparts. While lorikeets can survive on only 2.9% of a high-quality, highly digestible protein source, they may optimize their protein intake by selecting native species with significantly higher protein contents (>24%) and sufficient levels of essential amino acids. Substituting these pollens with inferior sources may result in essential amino acid deficiencies. There are a variety of commercial nectar substitutes on the market but the high vitamin A content of many of these products is excessively high (up to 28,000 IU kg⁻¹), possibly contributing to a number of reproductive failures and poor health in captive lorikeets, including iron storage disease.