Looking at the Dietary Habits, Health, and Distributions of Parrots Through the Lens of Geophagy to Improve Management Outcomes in Conservation Arks and Parks: A Metaphorical Salt Gathering Expedition

Abstract

A growing number of parrot species require conservation intervention. Whether carried out in “conservation parks” (i.e., in the wild) and/or “conservation arks” (i.e., in captivity), conservation endeavors involve protecting and/or providing whatever resources parrots need to remain healthy and reproduce. Since an animal’s health, welfare, and fitness are strongly influenced by its nutritional status, appropriate foodstuffs are among the most important of said resources. A robust working knowledge of parrots’ dietary habits is therefore vital to the success of parrot conservation efforts. The aim of this dissertation is to fill in a few of the gaps in our understanding of parrots’ dietary habits. Geophagy, the consumption of earthen materials, is often used as a lens through which to explore the dietary habits of parrots and achieve my aim. My goals were to: (1a) assess the current state of knowledge regarding parrots’ dietary habits, (1b) quantify reports of parrots consuming “alternate” foodstuffs (anything other than reproductive plant parts), (2a) explore the utility of vegetation indices and their derivatives in modelling Red-crowned Parrot (Amazona viridigenalis) distributions in a highly-modified landscape (general, nest, roost, etc.), (3a) study relationships between dietary sodium (Na) requirements and aqueous-type geophagy in captive Monk Parakeets (Myiopsitta monachus) throughout their reproductive calendar, and (5) use elemental compositions of eggshells of geophagous Peruvian Scarlet and Red-and-green Macaws’ (Ara macao and A. chloropterus) eggs to examine their health and reduced reproductive success. I found over 43% of parrot species’ dietary habits remain “poorly-resolved”. The consumption of alternate foodstuffs, including earthen materials, is widespread across the order. Red-crowned Parrot distributions could be modelled using vegetation indices and their derivatives. Captive Monk Parakeets remain healthy and reproduce effectively when consuming diets containing no more than 700 ppm [Na]; parrots dietary Na requirements are likely significantly less than 1500 ppm [Na]. Peruvian macaws likely engage in geophagy to satisfy more than one mineral deficiency but may be exposed to toxicant-type elements that negatively impact their health in the process. Further research regarding parrots’ dietary habits is needed to ultimately “stall the silence of the squawk” in both conservation arks and parks around the world.