Analysis of growth rate variables and postfeeding regurgitation in hand-reared Spix's macaw (Cyanopsitta spixii)...

The Spix's macaw, or little blue macaw (Cyanopsitta spixii), is one of the most critically endangered bird species in the world. In 1990, the Brazilian Nature Conservation Authority established a permanent committee to oversee the captive breeding of about 20 individual Spix's macaws held in various locations throughout the world. Al Wabra Wildlife Preservation (AWWP) successfully bred 10 Spix's macaws in the 2005 and 2006 breeding seasons but intermittent episodes of postfeeding regurgitation in hand-raised chicks prompted the need to better understand and monitor the nutritional and physiologic requirements of growing nestlings. To ascertain and rank the possible causes of regurgitation in chicks, we undertook a critical analysis of the feeding, growth, and health data recorded for each individual hand-raised chick. Factors such as the total daily food intake (TDFI), growth curves, nursery room climate (temperature and humidity), and nutritional requirements were investigated as well as any health issues. Chicks attained a maximum body weight of 375 +/- 25 g at 45 days and then gradually lost weight until they reached a weaning weight of 300 +/- 30 g. The maximum daily volume of food that each chick received was 101 +/- 29 g at 42 days of age, which was also the age at which a peak in postfeeding regurgitation episodes occurred. The TDFI as a percentage of body weight peaked (83.1 +/- 12.3%) at day 3 of age and dropped to 30.1 +/- 2.3% by day 45 and then to 19.6 +/- 1.1% at day 92. Detailed analyses of the 2005 and 2006 records indicate that the regurgitation episodes may be primarily the result of overfeeding during the second trimester of hand-rearing. Our results indicate that smaller meals during the period when chicks are attaining their maximum body weights may contribute to a decrease in the occurrence of regurgitation episodes in hand-reared Spix's macaws.